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20th Century 
Machine Shop Practice 



ARITHMETIC, PRACTICAL GEOMETRY, MENSURATION. APPLIED 
MECHANICS, PROPERTIES OF STEAM, THE INDICATOR, 
HORSEPOWER, ELECTRICITY, MEASURING DEVICES, 
MACHINISTS' TOOLS, SHOP TOOLS, MACHINE 
TOOLS, AUXILIARY MACHINES, PORTABLE 
TOOLS.IMISCELLANEOUS TOOLS, PLAIN 
AND SPIRAL INDEXING MACHINES, 
NOTES ON STEEL, GAS FUR- 
NACES, SHOP TALKS, SHOP 
KINKS, MEDICAL AID, 
TABLES 



OVER 400 ILLUSTRATIONS 
BY 

L. ELLIOTT BROOKES 

Author of the "Automobile Handbook," "Practical Gas and Oil Engine 
Handbook," and "The Calculation of Horsepower Made Easy." 




CHICAGO 
FREDERICK J. DRAKE & CO., PUBLISHERS 






Copyright 
By Frederick J. 


. 1915 
Drake, 

I 


& Co. 


Copyright 
By Frederick J. 


, 1906 
Drake & Co. 




X* 



z * 



M 12.915 



CI.A406294 



PREFACE. 



This work has been compiled for the use of Machinists, 
Engineers and others who are interested in the use and 
operation of the Machinery and Machine Tools in a modern 
machine shop, and every effort has been made by the author 
to deal with the subjects which come within the scope of this 
work in as practical and non-technical manner as possible. 
A great number of useful rules, formulas and tables are also 
given, and which will be found of untold value in connection 
with the subject matter of the book The author is indebted 
to the Brown & Sharpe Mfg. Co. for many of the illustrations 
and much of the information pertaining to Gear Cutting, 
Grinding and Milling Machines. 

THE AUTHOR. 



ARITHMETIC 



Arithmetic is the science of numbers, and as numbers 
treat of magnitude or quantity, whatever is capable of in- 
crease or decrease may be considered as of magnitude 01 
quantity. 

A Number is a unit or collection of units, as two, five, 
six. 

An Integer is a number which represents an unbroken 
quantity. 

An Odd Number is a number which cannot be divided 
by two. 

An Even Number is a number which can be exactly 
divided by two. 

Factors of a number are those numbers which, when 
multiplied together, make that number. 

A Prime Number is a number exactly divisible by one. 

An Exact Divisor is a whole number which will divide 
another number without a remainder. 

The Greatest Common Divisor of two or more numbers 
is the greatest number which will divide each of the num- 
bers exactly. 

A Multiple of a number is any number exactly divisible 
by that number. 

The Least Common Multiple of two or more numbers 
is the smallest number which is exactly divisible by each of 
the other numbers. 

Addition is uniting two or more numbers into one. The 
result of the adition is called the Sum. 

The sign of Addition is (+), thus: 90+10=100. 

Subtraction is taking a lesser sum from a greater one. 

The answer is called the Remainder or the Difference. 

The sign of Subtraction is (— ), thus 90—10=80. 

9 



10 MACHINE SHOP PRACTICE 

Multiplication is finding the amount of one number in- 
creased as many times as there are units in another. 

The answer is called the Product. 

The sign of Multiplication is (X), thus: 90X10=900. 

Division may be defined as the dividing of a number of 
quantity into any other number of parts. 

When one number has to be divided by another number, 
the first one is called the Dividend, and the second one 
the Divisor, and the result is the Quotient. 

The sign of Division is (h-), thus: 90^-10=9. 

A number is exactly divisible by 2 when the number 
ends in an even number or in 0, by 3, when the sum of 
the figures is exactly divisible by 3, by 4, when the num- 
ber formed by the last two figures of the number is ex- 
actly divisible by 4, by 5, when the number ends in 5 or 0. 

Addition. 

Example: Add together 397,495 and 6,350. 

397495 
6350 
403,845— Answer. 
Example: Add together 28,673 and 973. 

28673 
973 
29,646— Answer. 

Example: Add 6,593 to 37. 

6593 
37 

6,630— Answer. 

Subtraction. 

Example: Subtract 397,495 from 403,845. 

403845 
397495 
6,350— Answer. 



ARITHMETIC 11 



Example: Subtract 28,673 from 29,646. 

29646 
28673 



973— Answer. 



Example: Subtract 6,593 from 6,630. 

6630 
6593 



37— Answer 



Multiplication. 



Example: Multiply 144 by 12. 

144 
12 



288 
144 



1,728— Answer. 



Example: Multiply 3,645 by 468. 

3645 

468 



29160 
21870 
14580 



1,705,860— Answer. 

Example: Multiply 86,540 by 1,236. 

86540 
1236 



519240 
259620 
173080 
86540 
106,963,440— Answer. 



12 MACHINE SHOP PRACTICE 

Division. 
Example: Divide 12 into 1728. 

12)1728(144- Answer. 

52 

48 

"48 

Example: Divide 468 into 1,705,860. 

468)1705860 (3,645- Answer. 
1404 
3018 

2808 



2106 
1872 



2340 
2340 



Example: Divide 1,236 into 106,963,440. 

1236)106963440(86,540-Answer. 
9888 
8083 
7416 



6674 
6180 
4944 
4944 



Algebraic Signs and Symbols. 

= The sign of equality. It denotes that the quantities 
connected by this sign are equal to one another, thus: 12 
inches = 1 foot. 

-f- The sign of addition. It signifies plus or more, thus: 
7+5=12. 



ARITHMETIC 13 

— The sign of subtraction. It signifies minus or less, 
thus: 7—5=2. 

X The sign of multiplication. It denotes that the quan- 
tities connected by the sign are to be multiplied together, 
thus: 7X5=35. 

-f- This is the sign of division. It signifies divided by, 
thus: 7-^5=1.4. 

( ) or [ ] These signs are called brackets and denote that 
the numbers between them are to be taken collectively and 
treated as one quantity, thus: 12 (7+5) =12X12=1 44, 
12(7— 5)=12X2=24. 

— This sign is called the bar or vinculum. It is some- 
times used in place of the brackets, thus: 12 7-J-5 = 12y 
12=144, 12 7^5 = 12X2=24. 

Quantities in Algebra are expressed by letters and are 
used to shorten or simplify the formula, thus: aX^ signi- 
fies that a is to be multiplied by b. 

When it is desired to express division in a simple form, 
the division is written under the dividend, thus: (a-|-b)-^ 
c=a+b. 

a 2 This denotes that a is to be multiplied by itself, thus: 
aXa=a 2 , or is some number multiplied by itself, thus 
3X3=9. 

a 3 This signifies that a is to be multiplied by itself twice, 
thus: aXaX a ^ a3 > or it is some number multiplied by 
itself twice, thus: 3X3X 3 =27. 

V This is called the radical sign and when placed before 
a letter or number, denotes that some root of the number is 
to be extracted, thus: V a means the square root of a, or 
%/a means the cube root of a. 

Va 

, This signifies that the square root of a has to he e& 

tracted and then divided by b. 



14 MACHINE SHOP PRACTICE 



— jr This denotes that a is to be divided by the square 
root of b. 



v 



3i 

— This signifies that a is to be divided by b and the 

square root of the result extracted. 

:, : :, : These are the signs of proportion or the rule of 
three. The sign : means— is to, the sign :: means— as, 
thus: 1:4::4:16 or 1 is to 4 as 4 is to 16. 

°, ', " These signs are used to express the value of an 
angle in degrees, minutes and seconds, thus: 30 degrees, 20 
minutes, 10 seconds may be written 30° 20' 10". 

', " These two signs are also used to represent feet and 
inches, thus: 3 feet 6 inches may be written 3' 6". 

— The Greek letter is used to denote the ratio of the 
circumference of a circle to its diameter, which is 3.14159. 

g This sign is used to represent the value of the gravity 
constant, which is 32.2. 

Decimal Fractions. 

Decimal Fractions are those which have 10, 100, 1000, 
&e. for a denominator, and are expressed by writing the 
numerator only and placing a decimal point before it on the 
left hand, as for example: 

tV == -1 tVo = «76 t"oo""o =: «876 

T7 = »3 to"o = '03 -t"oo"o" == «003 

mo 1 1Q 3 113.3 11330 
'O — llOT^ T"0 T¥0~ 

-j -j o QQ 1 1 3 . 03 11 30-3 11 3 03 

Addition of Decimals. Arrange the numbers so that all 
the decimal points come directly under one another, add 
them together as in whole numbers, and point off as many 
figures for decimals as are equal to the greatest number of 
decimals in any of the given numbers. 



ARITHMETIC 

Example: Add together 3.79, .117, 87.225, 478.91 

3.79 
.117 
87.225 
478.91 
570.042 Answer. 



15 



Subtraction of Decimals. Place the numbers under one 
another, as in addition, subtract as in whole numbers, keep- 
ing the decimal point in the remainder directly under those 
above it. 

Example: From 97.378 
take 46.4972 

50.8808 Answer. 

Multiplication of Decimals. Multiply the factors to- 
gether, as in whole numbers, then point off from the 
product as many decimal places as there are in both fac- 
tors, supplying any deficiency by annexing ciphers to the 
left hand. 

Example: Multiply 4.735 
by .374 
18940 
33145 
14205 
1.770890 Answer. 

Example: Multiply .04735 
by .0374 
18940 
33145 
14205 



. 001770890 Answer. 

Division of Decimals. Remove the decimal point in the 
dividend as many places to the right as there are decimal 
places in the divisor and supply any deficiency by annexing 



16 MACHINE SHOP PRACTICE 

ciphers. Then make the divisor a whole number, and pro- 
ceed as in the division of simple numbers, and the quotient 
will contain as many decimal places as are used in the 
dividend. 
Example: Divide 74.23973 by 6.12. 

612)7423.973(12.130 Answer. 
612 



1303 
1224 
799 
612 


Example: Divide .7423973 by 612 

612). 7423973 (.0012130 Answer. 
612 


1877 
1836 


1303 
1224 


413 


799 



To Reduce any Vulgar Fraction to a Decimal. Annex 
ciphers to the numerator till it be equal to or grealer tha^ 
the denominator; divide by the denominator, as in division 
of decimals, and the quotient will be the decimal required. 

Reduce yjt to a decimal fraction. 
256) 7.00000000(. 02734375 Answer. 
512 



1880 
1792 




880 
768 


Reduce tV to a decimal fraction . 


1120 
1024 
960 
768 


12)7.00000000 

.58333333 Answer. 


1920 
1792 
1280 
1280 





ARITHMETIC 17 

Reading Decimals. When reading decimals, the idea of 
a denominator should be omitted and the decimals read, 
thus: .36 as point— 3-6, or .568 as point— 5— 6— 8. 
Examples of the use of decimal fractions: 
Add into one sum the following numbers: 

16.625, 11.4, 20.7831, 12.125, 8.04 and 7.002 

16.625 
11.4 
20.7831 
12.125 

8.04 

7.002 
75.9751 the sum required. 

Subtract 119.80764 from 234.98276 

234.98276 
119.80764 



115.17512 the remainder required. 

Subtract .002 from 100 

100. 
.002 
99.998 the remainder required. 

Multiply .002 by .016 

.002 
.016 



.00032 the product required. 



Multiply 62.10372 by 16.732 

62.10372 1 
16.732 
12420744 
18631116 
43472604 
37262232 
6210372 



1039.11944304 the product required. 



18 MACHINE SHOP PRACTICE 

Always notice that the number of figure3 in the product 
to the right of the decimal point equal to the number of 
decimals in the multiplier and multiplicand taken together. 

Roots of Numbers. 
To Extract the Square Root of a Number. If there be 
decimals in the given number, make them to consist of 
two, four, six, &c, places by annexing ciphers to the right 
hand. Then separate the whole into periods of two figures 
each, beginning at the right hand, and the left-hand period 
will consist of one or two figures, according as the number 
of figures in the whole number is .odd or even. Find a 
square number equal to or the next less than the left-hand 
period, and put the root of it in the quotient. Subtract this 
square from the left-hand period, and to the remainder 
bring down the next period for a dividend, and to the left 
hand of it write double the quotient for a divisor. Then 
consider what figure if annexed to the divisor and the re- 
sult multiplied by it the product may be equal to or the 
next less number than the dividend, and it will ba the 
second figure of the root. From the dividend subtract the 
product, and to the remainder bring down the next period 
for a new dividend. Double the figures in the quotient for 
a divisor, and continue the operation as above till all the 
periods are used. 

Example- Extract the square root of 10291264 
Example: Extract the square root of 177746.56 

10291264 I 3208 Answer. 177746.56 I 42.6 Answer, 

9 16 



62 
20 


129 
124 


6408 


1 51264 
51264 



82 

2 


177 
164 


841 1 1346 
l| 841 


842 


6 1 50556 
/ 50556 



ARITHMETIC 39 

To Extract the Square Root of a Vulgar Fraction. 

Reduce the given fraction to its lowest terms. Then 
extract the square root of the numerator for a new numera- 
tor, and the square root of the denominator for a new de- 
nominator. If the fraction will not extract even, reduce it 
to a decimal and then extract the square root. 

To Extract the Cube Root of a Number. 

If there be decimals in the given n amber, make them 
to consist of three, six, nine, &c, places by annexing 
ciphers to the right hand, if necessary. Then separate the 
whole into periods of three figures each, beginning at the 
right hand. The left-hand period may consist of one, two, 
or three figures. Find the nearest cube to the first period, 
subtract it therefrom, and put the root in the quotient. 
Then three times the square of this root will be the trial 
divisor for finding the next figure. Multiply the" root 
figure, or figures already found by three, and prefix the 
product to the next new root-figure, which will be seen by 
the trial divisor. Then multiply this number by the new 
root-figure, and place the product two figures to the right 
below the trial divisor, and add it to the trial divisor. This 
sum will be the true divisor. Under this divisor write the 
square of the last root-figure, which add to the two sums 
above, and the result is the next trial divisor. The true 
divisor being found as before directed. 



20 



MACHINE SHOP PRACTICE 



Example: Extract the cube root of 4088324799 



Truedhisor l 3 = 

Trial divisor 1 2 X3=3 

35X5=175 



True divisor 475X5 

5 8 = 25 
Trial divisor 675 

459X9= 4131 



71631X9 



9 ! 



81 



Trial divisor =75843 

4779X9= 43011 
True divisor 



4088324799 | 1599 Answer. 
1 



3088 



2375 



713324 



644679 



7627311X9 



68645799 



68645799 



The square and cube roots of numbers from 1 to 500 are 
given in the fourth and fifth column of Table No. 1. 



Reciprocals of Numbers. 

The Reciprocal of a Number is another number, which 
when multiplied by the original Number will give 1 or 
unity as a result. In other words the Reciprocal of a 
Number is the result obtained by dividing the number into 
1. The Reciprocals of Numbers will be found a great help 
as a substitute for Division in all ordinary calculations 
which are within the limits of the Table. 

Example: Divide 3 by 89. 

Answer: From Table No. 2 the reciprocal of 89 is found 
to be .011,2135, this multiplied by 3, equals .033,705, which 
is the same result as if 3 were divided by 89. 

Example: Divide 5 by 473. 

Answer: From Table No. 2 the reciprocal of 473 is 
.002,114, this multiplied by 5, gives .010,570 as the result, 
which is equivalent to dividing 5 by 473. 



ARITHMETIC 21 

The reciprocal of 367 is .002,724, the reciprocal of 36.7 
is .02724, the reciprocal of 3.67 is .2724, and the reciprocal 
of .367 is 2.724. 

In a like manner the reciprocal of any number within 
the limits of the Table may be found by simply moving 
the decimal point as shown. 

Table No. 1 gives the Squares, Cubes, Square and Cube 
Roots and the Reciprocals of numbers from 1 to 500 re- 
ipectively. 



22 



MACHINE SHOP PRACTICE 



Table No. 1- 


—Squares, 


Cubes, Square Roots, Cube 


Eoots and Reciprocals 


of Numbers from 1 


TO 500. 


No. 


Square 


Cube 


Square Root 


Cube Root 


Recipiocal 


1 


1 


1 


1.00000 


1.00000 


1.00000 


2 


4 


8 


1.41421 


1.25992 


.50000 


3 


9 


27 


1.73205 


1.44224 


.33333 


4 


16 


64 


2.00000 


1.58740 


.25000 


5 


25 


125 


2.23606 


1.70997 


.20000 


6 


36 


216 


2.44948 


1.81712 


.16666 


7 


49 


343 


2.64575 


1.91293 


.14285 


8 


64 


512 


2.82842 


2.00000 


.12500 


9 


81 


729 


3.00000 


2.08008 


.11111 


10 


100 


1000 


3.16227 


2.15443 


.10000 


11 


121 


1331 


3.31662 


2.22398 


.09090 


12 


144 


1728 


3.46410 


2.28942 


.08333 


13 


169 


2197 


3.60555 


2.35133 


.07602 


. 14 


196 


2744 


3.74165 


2.41014 


.07142 


15 


225 


3375 


3.87298 


2.46621 


.06666 


16 


256 


4096 


4.00000 


2.51984 


.06250 


17 


289 


4913 


4.12310 


2.57128 


.05882 


18 


324 


5832 


4.24264 


2.62074 


.05555 


19 


361 


6859 


4.35889 


2.66840 


.05263 


20 


400 


8000 


4.47213 


2.71441 


.05000 


21 


441 


9621 


4.58257 


2.75892 


.04761 


22 


484 


10648 


4.69041 


2.80203 


.04545 


23 


529 


12167 


4.79583 


2.84386 


.04347 


24 


576 


138(84 


4.89897 


2.88449 


.04166 


25 


625 


15625 


5.00000 


2.92401 


.04000 


26 


676 


17576 


5.09901 


2.96249 


.03846 


27 


729 


19683 


5.19615 


3.00000 


.03703 


28 


784 


21952 


5.29150 


3.03658 


.03571 


29 


841 


24389 


5.38516 


3.07231 


.03448 


30 


900 


27000 


5.47722 


3.10723 


.03333 


31 


961 


29791 


5.56776 


3.14138 


.03225 


32 


1024 


32768 


5.65685 


3.17480 


.03125 


33 


1089 


35937 


5.74456 


3.20753 


.03030 


34 


1156 


39304 


5.83095 


3.23961 


.02941 


35 


1225 


42875 


5.91607 


3.27106 


.02857 


36 


1296 


46656 


6.00000 


3.30192 


.02777 


37 


1369 


50653 


6.08276 


3.33222 


.02702 


38 


1444 


54872 


6.16441 


3.36197 


.02631 I 



ARITHMETIC 



23 





No. 


Square 


Cube 


Square Root 


Cube Root 


Reciprocal 






39 


1521 


59319 


6.24499 


3.39121 


.02564 






40 


1600 


64000 


6.32455 


3.41995 


.02500 






41 


1681 


68921 


6.40312 


3.44821 


.02439 






42 


1764 


74088 


6.48074 


3.47602 


.02380 






43 


1849 


79507 


6.55743 


3.50339 


.02325 






44 


1936 


85184 


6.63324 


3.53034 


.02272 






45 


2025 


91125 


6.70820 


3.55689 


.02222 






46 


2116 


97336 


6.78233 


3.58304 


.02173 






47 


2209 


103823 


6.85565 


3.60882 


.02127 






48 


2304 


110592 


6.92820 


3.63424 


.02083 






49 


2401 


117649 


7.00000 


3.65930 


.02040 






50 


2500 


125000 


7.07106 


3.68403 


.02000 






51 


2601 


132651 


7.14142 


3.70842 


.01960 






52 


2704 


140608 


7.21110 


3.73251 


.01923 






53 


2809 


148877 


7.28010 


3.75628 


.01886 






54 


2916 


157464 


7.34846 


3.77976 


.01851 






55 


3025 


166375 


7.41619 


3.80295 


.01818 






56 


3136 


175616 


7.48331 


3.82586 


.01785 






57 


3249 


185193 


7.54983 


3.84850 


.01754 






58 


3364 


195112 


7.61577 


3.87087 


.01724 






59 


3481 


205379 


7.68114 


3.89299 


.01694 






60 


3600 


216000 


7.74596 


3.91486 


.01666 






61 


3721 


226981 


7.81024 


3.93649 


.01639 






62 


3844 


238328 


7.87400 


3.95789 


.01612 






63 


3969 


250047 


7.93725 


3.97905 


.01587 






64 


4096 


262144 


8.00000 


4.00000 


.01562 






65 


4225 


274625 


8.06225 


4.02072 


.01538 






66 


4356 


287496 


8.12403 


4.04124 


.01515 






67 


4489 


300763 


8.18535 


4.06154 


.01492 






68 


4624 


314432 


8.24621 


4.08165 


.01470 






69 


4761 


328500 


8.30662 


4.10156 


.01449 






70 


4900 


343000 


8.36660 


4.12128 


.01428 






71 


5041 


357911 


8.42614 


4.14081 


.01408 






72 


5184 


373248 


8.48528 


4.16016 


.01388 






73 


5329 


389017 


8.54400 


4.17933 


.01369 






74 


5476 


405224 


8.60232 


4.19833 


.01351 






75 


5625 


421875 


8.66025 


4.21716 


.01333 






76 


5776 


438976 


8.71779 


4.23582 


.01315 






77 


5929 


456533 


8.77496 


4.25432 


.01298 






78 


6084 


474552 


8.83176 


4.27265 


.01282 






79 


6241 


493039 


8.88819 


4.29084 


.01265 






80 


6400 


512000 


8.94427 


4.30886 


.01250 





24 



MACHINE SHOP PRACTICE 



No. 


Square 


Cube 


Square Root 


Cube Root 


Reciprocal 


81 


6561 


531441 


9.00000 


4.32674 


.01234 


82 


6724 


551368 


9.05538 


4.34448 


.01219 


83 


6889 


571787 


9.11043 


4.36207 


.01204 


84 


7056 


592704 


9.16515 


4.37951 


.01190 


85 


7225 


614125 


9.21954 


4.39682 


.01176 


86 


7396 


636056 


9.27361 


4.41400 


.01162 


87 


7569 


658503 


9.32737 


4.43104 


.01149 


88 


7744 


681472 


9.38083 


4.44796 


.01136 


89 


7921 


704969 


9.43398 


4.46474 


.01123 


90 


8100 


729000 


9.48683 


4.48140 


.01111 


91 


8281 


753571 


9.53939 


4.49794 


.01098 


92 


8464 


778688 


9.59166 


4.51435 


.01086 


93 


8649 


804357 


9.64365 


4.53065 


.01075 


94 


8836 


830584 


9.69535 


4.54683 


.01063 


95 


9025 


857375 


9.74679 


4.56290 


.01052 


96 


9216 


884736 


9.79795 


4.57885 


.01041 


97 


9409 


912673 


9.84885 


4.59470 


.01030 


98 


9604 


941192 


9.89949 


4.61043 


.01020 


99 


9801 


970299 


9.94987 


4.62606 


.01010 


100 


10000 


1000000 


10.00000 


4.64158 


.01000 


101 


10201 


1030301 


10.04987 


4.65700 


.00990 


102 


10404 


1061208 


10.09950 


4.67232 


.00980 


103 


10609 


1092727 


10.14889 


4.68754 


.00970 


104 


10816 


1124864 


10.19803 


4.70266 


.00961 


105 


11025 


1157625 


10.24695 


4.71769 


.00952 


106 


11236 


1191016 


10.29563 


4.73262 


.00943 


107 


11449 


1225043 


10.34408 


4.74745 


.00934 


108 


11664 


1259712 


10.39230 


4.76220 


.00925 


109 


11881 


1295029 


10.44030 


4.77685 


.00917 


110 


12100 


1331000 


10.48808 


4.79141 


.00909 


111 


12321 


1367631 


10.53565 


4.80589 


.00900 


112 


12544 


1404928 


10.58300 


4.82028 


.00892 


113 


12769 


1442897 


10.63014 


4.83458 


.00884 


114 


12996 


1481544 


10.67707 


4.84880 


.00877 


115 


13225 


1520875 


10.72380 


4.86294 


.00869 


116 


13456 


1560896 


10.77032 


4.87699 


.00862 


117 


13689 


1601613 


10.81665 


4.89097 


.00854 


118 


13924 


1643032 


10.86278 


4.90486 


.00847 


119 


14161 


1685159 


10.90871 


4.91868 


.00840 


120 


14400 


1728000 


10.95445 


4.93242 


.00833 


121 


14641 


1771561 


11.00000 


4.94608 


.00826 


122 


14884 


1815848 


11.04536 


4.95967 


.00819 



ARITHMETIC 



25 



No. 


Square 


Cube 


Square Root 


Cube Root 


Reciprocal 


123 


15129 


1860867 


11.09053 


4.97318 


.00813 


124 


15376 


1906624 


11.13552 


4.98663 


.00806 


125 


15625 


1953125 


11.18033 


5.00000 


.00800 


126 


15876 


2000376 


11.22497 


5.01329 


.00793 


127 


16129 


2048383 


11.26942 


5.02652 


.00787 


128 


16384 


2097152 


11.31370 


5.03968 


.00781 


129 


16641 


2146689 


11.35781 


5.05277 


.00775 


±30 


16900 


2197000 


11.40175 


5.06579 


.00769 


131 


17161 


2248091 


11.44552 


5.07875 


.00763 


132 


17424 


2299968 


11.48912 


5.09164 


.00757 


133 


17689 • 


2352637 


11.53256 


5.10446 


.00751 


134 


17956 


2406104 


11.57583 


5.11722 


.00746 


135 


18225 


2460375 


11.61895 


5.12992 


.00740 


136 


18496 


2515456 


11.66190 


5.14256 


.00735 


137 


18769 


2571353 


11.70469 


5.15513 


.00729 


138 


19044 


2628072 


11.74734 


5.16764 


.00724 


139 


19321 


2685619 


11.78982 


5.18010 


.00719 


140 


19600 


2744000 


11.83215 


5.19249 


.00714 


141 


19881 


2803221 


11.87434 


5.20482 


.00709 


142 


20164 


2863288 


11.91637 


5.21710 


.00704 


143 


20449 


2924207 


11.95826 


5.22932 


.00699 


144 


20736 


2985984 


12.00000 


5.24148 


.00694 


145 


21025 


3048625 


12.04159 


5.25358 


.00689 


146 


21316 


3112136 


12.08304 


5.26563 


.00684 


147 


21609 


3176523 


12.12435 


5.27763 


.00680 


148 


21904 


3241792 


12.16552 


5.28957 


.00675 


149 


22201 


3307949 


12.20655 


5.30145 


.00671 


150 


22500 


3375000 


12.24744 


5.31329 


.00666 


151 


22801 


3442951 


12.28820 


5.32507 


.00662 


152 


23104 


3511808 


12.32882 


5.33680 


.00657 


153 


23409 


3581577 


12.36931 


5.34848 


.00653 


154 


23716 


3652264 


12.40967 


5.36010 


.00649 


155 


24025 


3723875 


12.44989 


5.37168 


.00645 


156 


24336 


3796416 


12.48999 


5.38321 


.00641 


157 


24649 


3869893 


12.52996 


5.39469 


.00636 


158 


24964 


3944312 


12.56980 


5.40612 


.00632 


159 


25281 


4019679 


12.60952 


5.41750 


.00628 


160 


25600 


4096000 


12.64911 


5.42883 


.00625 


161 


25921 


4173281 


12.68857 


5.44012 


.00621 


162 


26244 


4251528 


12.72792 


5.45136 


.00617 


163 


26569 


4330747 


12.76714 


5.46255 


.00613 


164 


26896 


4410944 


12.80624 


5.47370 


.00609 



26 



MACHINE SHOP PRACTICE 



No. 
165 


Square 


Cube 


Square Root 


Cube Root 


Reciprocal 


27225 


4492125 


12.84523 


5.48480 


.00606 


166 


27556 


4574296 


12.88409 


5.49586 


.00602 


167 


27889 


4657463 


12.92284 


5.50687 


.00598 


168 


28224 


4741632 


12.96148 


5.51784 


.00595 


169 


28561 


4826809 


13.00000 


5.52877 


.00591 


170 


28900 


4913000 


13.03840 


5.53965 


.00588 


171 


29241 


5000211 


13.07669 


5.55049 


.00584 


172 


29584 


5088448 


13.11487 


5.56129 


.00581 


173 


29929 


5177717 


13.15294 


5.57205 


.00578 


174 


30276 


5268024 


13.19090 


5.58277 


.00574 


175 


30625 


5359375 


13.22875 


5.5.9344 


.00571 


176 


30976 


5451776 


13.26649 


5.60407 


.00568 


177 


31329 


5545233 


13.30413 


5.61467 


.00564 


178 


31684 


5639752 


13.34166 


5.62522 


.00561 


179 


32041 


5735339 


13.37908 


5.63574 


.00558 


180 


32400 


5832000 


13.41640 


5.64621 


.00555 


181 


32761 


5929741 


13.45362 


5.65665 


.00552 


182 


33124 


6028568 


' 13.49073 


5.66705 


.00549 


183 


33489 


6128487 


13.52774 


5.67741 


.00546 


184 


33856 


6229504 


13.56466 


5.68773 


.00543 


185 


34225 


6331625 


13.60147 


5.69801 


.00540 


186 


34596 


6434856 


13.63818 


5.70826 


.00537 


187 


34969 


6539203 


13.67479 


5.71847 


.00534 


188 


35344 


6644672 


13.71130 


5.72865 


.00531 


189 


35721 


6751269 


13.74772 


5.73879 


.00529 


190 


36100 


6859000 


13.78404 


5.74889 


.00526 


191 


36481 


6967871 


13.82027 


5.75896 


.00523 


192 


36864 


7077888 


13.85640 


5.76899 


.00520 


193 


37249 


7189057 


13.89244 


5.77899 


.00518 


194 


37636 


7301384 


13.92838 


5.78896 


.00515 


195 


38025 


7414875 


13.96424 


5.79889 


.00512 


196 


38416 


7529536 


14.00000 


5.80878 


.00510 


197 


38809 


7645373 


14.03566 


5.81864 


.00507 


198 


39204 


7762392 


14.07124 


5.82847 


.00505 


199 


39601 


7880599 


14.10673 


5.83827 


.00502 


200 


40000 


8000000 


14.14213 


5.84803 


.00500 


201 


40401 


8120601 


14.17744 


5.85776 


.00497 


202 


40804 


8242408 


14.21267 


5.86746 


.00495 


203 


41209 


8365427 


14.24780 


5.87713 


.00492 


204 


41616 


8489664 


14.28285 


5.88676 


.00490 


205 


42025 


8615125 


14.31782 


5.89636 


.00487 


206 


42436 


8741816 


14.35270 


5.90594 


.00485 



ARITHMETIC 



27 



No. 


Square 


Cube 


Square Root 


Cube Root 


Reciprocal 


207 


42849 


8869743 


14.38749 


5.91548 


.00483 


208 


43264 


8998912 


14.42220 


5.92499 


.00480 


209 


43681 


9129329 


14.45683 


5.93447 


.00478 


210 


44100 


9261000 


14.49137 


5.94392 


.00476 


211 


44521 


9393931 


14.52583 


5.95334 


.00473 


212 


44944 


9528128 


14.50021 


5.96273 


.00471 


213 


45369 


9663597 


14.59451 


5.97209 


.00469 


214 


45796 


9800344 


14.62873 


5.98142 


.00467 


215 


46225 


9938375 


14.66287 


5.99072 


.00465 


216 


46656 


10077696 


14.69693 


6.00000 


.00462 


217 


47089 


10218313 


14.73091 


6.00924 


.00460 


218 


47524 


10360232 


14.76482 


6.01846 


.00458 


219 


47961 


10503459 


14.79864 


6.02765 


.00456 


220 


48400 


10648000 


14.83239 


6.03681 


.00454 


221 


48841 


10793861 


14.86606 


6.04594 


.00452 


222 


49284 


10941048 


14.89966 


6.05504 


.00450 


223 


49729 


11089567 


14.93318 


6.06412 


.00448 


224 


50176 


11239424 


14.98662 


6.07317 


.00446 


225 


50625 


11390625 


15.00000 


6.08220 


.00444 


226 


51076 


11543176 


15.03329 


6.09119 


.00442 


227 


51529 


11697083 


15.06651 


6.10017 


.00440 


228 


51984 


11852352 


15.09966 


6.10911 


.00438 


229 


52441 


12008989 


15.13274 


6.11803 


.00436 


230 


52900 


12167000 


15.16575 


6.12692 


.00434 


231 


53361 


12326391 


15.19868 


6.13579 


.00432 


232 


53824 


12487168 


15.23154 


6.14463 


.00431 


233 


54289 


12649337 


15.26433 


6.15344 


.00429 


234 


54756 


12812904 


15.29705 


6.16224 


.00427 


235 


55225 


12977875 


15.32970 


6.17100 


.00425 


236 


55696 


13144256 


15.36229 


6.17974 


.00423 


237 


56169 


13312053 


15.39480 


6.18846 


.00421 


238 


56644 


13481272 


15.42724 


6.19715 


.00420 


239 


57121 


13651919 


15.45962 


6.20582 


.00418 


240 


57600 


13824000 


15.49193 


6.21446 


.00416 


241 


58081 


13997521 


15.52417 


6.22308 


.00414 


242 


58564 


14172488 


15.55634 


6 23167 


.00413 


243 


59049 


14348907 


15.58845 


6.24025 


.00411 


244 


59536 


14526784 


15.62049 


6.24879 


.00409 


245 


60025 


14706125 


15.65247 


6.25732 


.00408 


246 


60516 


14886936 


15.68438 


6.26582 


.00406 


247 


61009 


15069223 


15.71623 


6.27430 


.00404 


248 


61504 


15252992 


15.74801 


6.28276 


.00403 



28 



MACHINE SHOP PRACTICE 



No. 


Square 


Cube 


Square Root 


Cube Root 


Reciprocal 


249 


62001 


15438249 


15.77973 


6.29119 


.00401 


250 


62500 


15625000 


15.81138 


6.29960 


.00400 


251 


63001 


15813251 


15.84297 


6.30799 


.00398 


252 


63504 


16003008 


15.87450 


6.31635 


.00396 


253 


64009 


16194277 


15.90597 


6.32470 


.00395 


254 


64516 


16387064 


15.93737 


6.33302 


.00393 


255 


65025 


16581375 


15.96871 


6.34132 


.00392 


256 


65536 


16777216 


16.00000 


6.34960 


.00390 


257 


66049 


16974593 


16.03121 


6.35786 


.00389 


258 


66564 


17173512 


16.06237 


6.36609 


.00387 


259 


67081 


17373979 


16.09347 


6.37431 


.00386 


260 


67600 


17576000 


16.12451 


6.38250 


.00384 


261 


68121 


17779581 


16.15549 


6.39067 


.00383 


262 


68644 


17984728 


16.18641 


6.39882 


.00381 


263 


69169 


18191447 


16.21727 


6.40695 


.00380 


264 


69696 


18399744 


16.24807 


6.41506 


.00378 


265 


70225 


18609625 


16.27882 


6.42315 


.00377 


266 


70756 


18821096 


16.30950 


6.43122 


.00375 


267 


71289 


19034163 


16.34013 


6.43927 


.00374 


268 


71824 


19248832 


16.37070 


6.44730 


.00373 


269 


72361 


19465109 


16.40121 


6.45531 


.00371 


270 


72900 


19683000 


16.43167 


6.46330 


.00370 


271 


73441 


19902511 


16.46207 


6.47127 


.00369 


272 


73984 


20123648 


16.49242 


6.47922 


.00367 


273 


74529 


20346417 


16.52271 


6.48715 


.00366 


274 


75076 


20570824 


16.55294 


6.49506 


.00364 


275 


75625 


20796875 


16.58312 


6.50295 


.00363 


276 


76176 


21024576 


16.61324 


6.51083 


.00362 


277 


76729 


21253933 


16.64331 


6.51868 


00361 


278 


77284 


21484952 


16.67333 


6.52651 


.00359 


279 


77841 


21717639 


16.70329 


6.53433 


.00358 


280 


78400 


21952000 


16.73320 


6.54213 


.00357 


281 


78961 


22188041 


16.76305 


6.54991 


.00355 


282 


79524 


22425768 


16.79285 


6.55767 


.00354 


283 


80089 


22665187 


16.82260 


6.56541 


.00353 


284 


80656 


22906304 


16.85229 


6.57313 


.00352 


285 


81225 


23149125 


16.88194 


6.58084 


.00350 


286 


81796 


23393656 


16.91153 


6.58853 


.00349 


287 


82369 


23639903 


16.94107 


6.59620 


.00348 


288 


82944 


23887872 


16.97056 


6.60385 


.00347 


289 


83521 


24137569 


17.00000 


6.61148 


.00346 


290 


84100 


24389000 


17.02938 


6.61910 


.00344 



ARITHMETIC 



29 



No. 


Square 


Cube 


Square Root 


Cube Root 
6.62670 


Reciprocal 


291 


84681 


24642171 


17.05872 


.00343 


292 


85264 


24897088 


17.08800 


6.63428 


.00342 


293 


85849 


25153757 


17.11724 


6.64185 


.00341 


294 


86436 


25412184 


17.14642 


6.64939 


.00340 


295 


87025 


25672375 


17.17556 


6.65693 


.00338 


296 


87616 


25934336 


17.20465 


6.66444 


.00337 


297 


88209 


26198073 


17.23368 


6.67194 


.00336 


298 


88804 


26463592 


17.26267 


6.67942 


.00335 


299 


89401 


26730899 


17.29161 


6.68688 


.00334 


300 


90000 


27000000 


17.32050 


6.69432 


.00333 


301 


90601 


27270901 


17.34935 


6.70175 


.00332 


302 


91204 


27543608 


17.37814 


6.70917 


.00331 


303 


91809 


27818127 


17.40689 


6.71657 


.00330 


304 


92416 


28094464 


17.43559 


6.72395 


.00328 


305 


93025 


28372625 


17.46424 


6.73131 


.00327 


306 


93636 


28652616 


17.49285 


6.73866 


.00326 


307 


94249 


28934443 


17.52141 


6.74599 


.00325 


308 


94864 


29218112 


17.54992 


6.75331 


.00324 


309 


95481 


29503629 


17.57839 


6.76061 


.00323 


310 


96100 


29791000 


17.60681 


6.76789 


.00322 


311 


93721 


30080231 


17.63519 


6.77516 


.00321 


312 


97344 


30371328 


17.66352 


6.78242 


.00320 


313 


97969 


30664297 


17.69180 


6.78966 


.00319 


314 


98596 


30959144 


17.72004 


6.79688 


.00318 


315 


99225 


31255875 


17.74823 


6.80409 


.00317 


316 


99856 


31554496 


17.77638 


6.81128 


.00316 


317 


100489 


31855013 


17.80449 


6.81846 


.00315 


318 


101124 


32157432 


17.83255 


6.82562 


.00314 


319 


101761 


32461759 


17.86057 


6.83277 


.00313 


320 


102400 


32768000 


17.88854 


6.83990 


.00312 


321 


103041 


32076161 


17.91647 


6.84702 


.00311 


322 


103684 


33386248 


17.94435 


6.85412 


.00310 


323 


104329 


33698267 


17.97220 


6.86121 


.00309 


324 


104976 


34012224 


18.00000 


6.86828 


.00308 


325 


105625 


34328125 


18.02775 


6.87534 


,00307 


326 


106276 


34645976 


18.05547 


6.88238 


.00306 


327 


106929 


34965783 


18.08314 


6.88941 


.00305 


328 


107584 


35287552 


18.11077 


6.89643 


.00304 


329 


108241 


35611289 


18.13835 


6.90343 


.00303 


330 


108900 


35937000 


18.16590 


6.91042 


.00303 


331 


109561 


36264691 


18.19340 


6.91739 


.00302 


332 


110224 


36594368 


18.22086 


6.92435 


.00301 



30 



MACHINE SHOP PRACTICE 



No. 
333 


Square 


Cube 


Square Root 


Cube Root 


Reciprocal 


110889 


36926037 


18.24828 


6.93130 


.00300 


334 


111556 


37259704 


18.27566 


6.93823 


.00299 


335 


112225 


37595375 


18.30300 


6.94514 


•00298 


336 


112896 


37933056 


18.33030 


6.95205 


.00297 


337 


113569 


38272753 


18.35755 


6.95894 


.00296 


338 


114244 


38614472 


18.38477 


6.96581 


.00295 


339 


114921 


38958219 


18.41195 


6.97268 


.00294 


340 


115600 


39304000 


18.43908 


6.97953 


.00294 


341 


116281 


39651821 


18.46618 


6.98636 


.00293 


342 


116964 


40001688 


18.49324 


6.99319 


.00292 


343 


117649 


40353607 


18.52025 


7.00000 


.00291 


344 


118336 


40707584 


18.54723 


7.00679 


.00290 


345 


119025 


41063625 


18.57417 


7.01357 


.00289 


346 


119716 


41421736 


18.60107 


7.02034 


.00289 


347 


120409 


41781923 


18.62793 


7.02710 


.00288 


348 


121104 


42144192 


18.65475 


7.03384 


.00287 


349 


121801 


42508549 


18.68151 


7.04058 


.00286 


350 


122500 


42875000 


18.70828 


7.04729 


.00285 


351 


123201 


43243551 


18.73499 


7.05400 


.00284 


352 


123904 


43614208 


18.76166 


7.06069 


.00284 


353 


124609 


43986977 


18.78829 


7.06737 


.00283 


354 


125316 


44361864 


18.81488 


7.07404 


.00282 


355 


126025 


44738875 


18.84144 


7.08069 


.00281 


356 


126736 


45118016 


18.86796 


7.08734 


.00280 


357 


127449 


45499293 


18.89444 


7.09397 


.00280 


358 


128164 


45882712 


18.92088 


7.10058 


.00279 


359 


128881 


46268279 


18.94729 


7.10719 


.00278 


360 


129600 


46656000 


18.97366 


7.11378 


.00277 


361 


130321 


47045881 


19.00000 


7.12036 


.00277 


362 


131044 


47437928 


19.02629 


7.12693 


.00276 


363 


131769 


47832147 


19.05255 


7.13349 


.00275 


384 


132496 


48228544 


19.07878 


7.14003 


.00274 


365 


133225 


48627125 


19.10497 


7.14656 


.00273 


366 


133956 


49027896 


19.13112 


7.15309 


.00273 


367 


134689 


49430863 


19.15724 


7.15959 


.00272 


368 


135424 


49836032 


19.18332 


7.16609 


.00271 


369 


136161 


50243409 


19.20937 


7.17258 


.00271 


370 


136900 


50653000 


19.23538 


7.17905 


.00270 


371 


137641 


51064811 


19.26136 


7.18551 


.00269 


372 


138384 


51478848 


19.28730 


7.19196 


.00268 


373 


139129 


51895117 


19.31320 


7.19840 


.00268 


374 


139876 


52313624 


19.33907 


7.20483 


.00267 



ARITHMETIC 



31 



No. 


Square 


Cube 


Square Root 


Cube Root 


Reciprocal 


375 


140625 


52734375 


19.36491 


7.21124 


.00266 


376 


141376 


53157376 


19.39071 


7.21765 


.00265 


377 


142129 


53582633 


19.41648 


7.22404 


.00265 


378 


142884 


54010152 


19.44222 


7.23042 


.00264 


379 


143641 


54439939 


19.46792 


7.23679 


.00263 


380 


144400 


54872000 


19.49358 


7.24315 


.00263 


381 


145161 


55306341 


19.51922 


7.24950 


.00262 


3S2 


145924 


55742968 


19.54482 


7.25584 


.00261 


383 


146689 


56181887 


19.57038 


7.26216 


.00261 


384 


147456 


56623104 


19.59591 


7.26848 


.00260 


385 


148225 


57066625 


19.62141 


7.27478 


.00259 


386 


148996 


57512456 


19.64688 


7.28107 


.00259 


387 


149769 


57960603 


19.67231 


7.28736 


.00258 


388 


150544 


58411072 


19.69771 


7.29363 


.00257 


389 


151321 


58863869 


19.72308 


7.29989 


.00257 


390 


152100 


59319000 


19.74841 


7.30614 


.00256 


391 


152881 


59776471 


19.77371 


7.31238 


.00255 


392 


153664 


60236288 


19.79898 


7.31861 


.00255 


393 


154449 


60698457 


19.82422 


7.32482 


.00254 


394 


155236 


61162984 


19.84943 


7.33103 


.00253 


395 


156025 


61629875 


19.87460 


7.33723 


.00253 


396 


156816 


62099136 


19.89974 


7.34342 


.00252 


397 


157609 


62570773 


19.92485 


7.34959 


.00251 


398 


158404 


63044792 


19.94993 


7.35576 


.00251 


399 


159201 


63521199 


19.97498 


7.36191 


.00250 


400 


160000 


64000000 


20.00000 


7.36806 


.00250 


401 


160801 


64481201 


20.02498 


7.37419 


.00249 


402 


161604 


64964808 


20.04993 


7.38032 


.00248 


403 


162409 


65450827 


20.07485 


7.38643 


.00248 


404 


163216 


65939264 


20.09975 


7.39254 


.00247 


405 


164025 


66430125 


20.12461 


7.39863 


.00246 


406 


164836 


66923416 


20.14944 


7.40472 


.00246 


407 


165649 


67419143 


20.17424 


7.41079 


.00245 


408 


166464 


67917312 


20.19900 


7.41685 


.00245 


409 


167281 


68417929 


20.22374 


7.42291 


.00244 


410 


168100 


68921000 


20.24845 


7.42895 


.00243 


411 


168921 


69426531 


20.27313 


7.43499 


.00243 


412 


169744 


69934528 


20.29778 


7.44101 


.00242 


413 


170569 


70444997 


20.32240 


7.44703 


.00242 


414 


171396 


70957944 


20.34698 


7.45303 


.00241 


415 


172225 


71473375 


20.37154 


7.45903 


.00240 


416 


173056 


71991296 


20.39607 


7.46502 


.00240 



32 



MACHINE SHOP PRACTICE 



No. 


Square 


Cube 


Square Root 


Cube Root 


Reciproca 


417 


173889 


72511713 


20.42057 


7.47099 


.00239 


418 


174724 


73034632 


20.44504 


7.47696 


.00239 


419 


175561 


73560059 


20.46948 


7.48292 


.00238 


420 


176400 


74088000 


20.49390 


7.48887 


.00238 


421 


177241 


74618461 


20.51828 


7.49481 


.00237 


422 


178084 


75151448 


20.54263 


7.50074 


.00236 


423 


178929 


75686967 


20.56696 


7.50666 


.00236 


424 


179776 


76225024 


20.59126 


7.51257 


.00235 


425 


180625 


76765625 


20.61552 


7.51847 


.00235 


426 


181476 


77308776 


20.63976 


7.52436 


.00234 


427 


182329 


77854483 


20.66397 


7.53024 


.00234 


428 


183184 


. 78402752 


20.68816 


7.53612 


.00233 


429 


184041 


78953589 


20.71231 


7.54198 


.00233 


430 


184900 


79507000 


20.73644 


7.54784 


.00232 


431 


185761 


80062991 


20.76053 


7.55368 


.00232 


432 


186624 


80621568 


20.78460 


7.55952 


.00231 


433 


187489 


81182737 


20.80865 


7.56535 


.00230 


434 


188356 


81746504 


20.83266 


7.57117 


.00230 


435 


189225 


82312875 


20.85665 


7.57689 


.00229 


436 


190096 


82881856 


20.88061 


7.58278 


.00229 


437 


190969 


83453453 


20.90454 


7.58857 


.00228 


438 


191844 


84027672 


20.92844 


7.59436 


.00228 


439 


192721 


84604519 


20.95232 


7.60013 


.00227 


440 


193600 


85184000 


20.97617 


7.60590 


.00227 


441 


194481 


85766121 


21.00000 


7.61166 


.00226 


442 


195364 


86350888 


21.02379 


7.61741 


.00226 


443 


196249 


86938307 


21.04756 


7.62315 


.00225 


444 


197136 


87528384 


21.07130 


7.62888 


.00225 


445 


198025 


88121125 


21.09502 


7.63460 


.00224 


446 


198916 


88716536 


21.11871 


7.64032 


.00224 


447 


199809 


89314623 


21.14237 


7.64602 


.00223 


448 


200704 


89915392 


21.16601 


7.65172 


.00223 


449 


201601 


90518849 


21.18962 


7.65741 


.00222 


450 


202500 


91125000 


21.21320 


7.66309 


.00222 


451 


203401 


91733851 


21.23676 


7.66876 


.00221 


452 


204304 


92345408 


21.26029 


7.67443 


.00221 


453 


205209 


92959677 


21.28379 


7.68008 


.00220 


454 


206116 


93576664 


21.30727 


7.68573 


.00220 


455 


207025 


94196375 


21.33072 


7.69137 


.00219 


456 


207936 


94818816 


21.35415 


7.69700 


.00219 


457 


208849 


95443993 


21.37755 


7.70262 


.00218 


458 


209764 


96071912 


21.40093 


7.70823 


.00218 1 



ARITHMETIC 



33 



No. 


Squaie 


Cube 


Square Root 


Cube Root 


Reciprocal 


459 


210681 


96702579 


21.42428 


7.71384 


.00217 


460 


211600 


97336000 


21.44761 


7.71944 


.00217 


461 


212521 


97972181 


21.47091 


7.72503 


.00216 


462 


213444 


98611128 


21.49418 


7.73061 


.00216 


463 


214369 


99252847 


21.51743 


7.73618 


.00215 


464 


215296 


99897344 


21.54065 


7.74175 


.00215 


465 


216225 


100544625 


21.56385 


7.74731 


.00215 


466 


217156 


101194696 


21.58703 


7.75286 


.00214 


467 


218089 


101847563 


21.61018 


7.75840 


.00214 


468 


219024 


102503232 


21.63330 


7.76393 


.00213 


469 


219961 


103161709 


21.65640 


7.76946 


.00213 


470 


220900 


103823000 


21.67948 


7.77498 


.00212 


471 


221841 


104487111 


21.70253 


7.78049 


.00212 


472 


222784 


105154048 


21.72556 


7.78599 


.00211 


473 


223729 


105823817 


21.74856 


7.79148 


.00211 


474 


224676 


106496424 


21.77154 


7.79697 


.00210 


475 


225625 


107171875 


21.79449 


7.80245 


.00210 


476 


226576 


107850176 


21.81742 


7.80792 


.00210 


477 


227529 


108531333 


21.84032 


7.81338 


.00209 


478 


228484 


109215352 


21.86321 


7.81884 


.00209 


479 


229441 


109902239 


21.88606 


7.82429 


.00208 


480 


230400 


110592000 


21.90890 


7.82973 


.00208 


481 


231361 


111284641 


21.93171 


7.83516 


.00207 


482 


232324 


111980168 


21.95449 


7.84059 


.00207 


483 


233289 


112678587 


21.97726 


7.84601 


.00207 


484 


234256 


113379904 


22.00000 


7.85142 


.00206 


485 


235225 


114084125 


22.02271 


7.85682 


.00206 


486 


236196 


114791256 


22.04540 


7.86222 


.00205 


487 


237169 


115501303 


22.06807 


7.86761 


.00205 


488 


238144 


116214272 


22.09072 


7.87299 


.00204 


489 


239121 


116930169 


22.11334 


7.87836 


.00204 


490 


240100 


117649000 


22.13594 


7.88373 


.00204 


491 


241081 


118370771 


22.15851 


7.88909 


.00203 


492 


242064 


119095488 


22.18107 


7.89454 


.00203 


493 


243049 


119823157 


22.20360 


7.89979 


.00202 


494 


244036 


120553784 


22.22611 


7.90512 


.00202 


495 


245025 


121287375 


22.24859 


7.91045 


.00202 


496 


246016 


122023936 


22.27105 


7.91578 


.00201 


497 


247009 


122763473 


22.29349 


7.92109 


.00201 


498 


248004 


123505992 


22.31591 


7.92640 


.00200 


499 


249001 


124251499 


22.33830 


7.93171 


.00200 


500 


250000 


125000000 


22.36067 


7.93700 


.00200 



34 MACHINE SHOP PRACTICE 

Logarithms of Numbers. 

Logarithms are the exponents of a series of powers and 
roots of numbers. The logarithm of a number is that ex- 
ponent of some other number, which renders the powe? of 
the other number, which is denoted by the exponent, equ .1 
to the former. In other words the logarithm of a number 
is the exponent of the power to which the number must be 
raised to give a given base. 

When the logarithms of numbers from a series in arith- 
metical progression, their corresponding natural numbers 
form a series in geometrical progression, thus: 

Common logarithms 12 3 4 

Natural numbers 1 10 100 1,000 10,000 

Natural logarithms were the invention of Lord Napier. 
Common logarithms, the kind in general use, were invented 
by Prof. Briggs of Oxford, England. Logarithms are ex- 
tremely useful in shortening the labor of mathematical cal- 
culations. 

The addition and subtraction of common logarithms cor- 
respond to the multiplication and division of their natural 
numbers. 

In a like manner, involution is performed by multiplying 
the common logarithm of any number by the number denot- 
ing the required power, and evolution by divid'ng the com- 
mon logarithm of the number denoting the required root. 

The common logarithm of a number consists of two parts, 
an integral part or whole number, which is called the 
characteristic, and a decimal called the mantissa. 

To find the common logarithm of a given number from 
Table No. 2, proceed as follows: 

The first two figures of the number will be found in the 
vertical column to the extreme left in the table, and the 
third figure of the number in the horizontal row at either 
the top or bottom of the table. Having found the first two 
figures of the number, always neglecting the decimal, pass 



ARITHMETIC 35 

along the line opposite these figures until the column headed 
by the third figure of the number is reached. The number 
thus found will be the mantissa or decimal fraction of the 
logarithm. The characteristic will depend upon the number 
of integers or whole numbers, less one, in the number, 
counting from the left of the decimal point. If the deci- 
mal point be entirely to the left of the number, the charac- 
teristic is obtained by counting the number of cyphers be- 
fore the first number, to the right and adjacent to the 
decimal point. 

Example: Find the common logarithm of 5.06 from 
Table No. 2. 

Answer: In the row of figures opposite 50 and in the 
column under 6, the mantissa of the logarithm is .7042 1 . 
Counting from the decimal place of the number to the left, 
the characteristic will be one less than the number of fig- 
ures to the right of the decimal point, which is, in this case 
1, and 1 minus 1 equals zero, which is the characteristic of 
the mantissa .7042, the complete logarithm of 5.06 will then 
be 0.7042. 

The logarithm of 0.506 is — 1.7042 

The logarithm of 5.06 is 0.7042 

The logarithm of 50.6 is 1.7042 

The logarithm of 506 is 2.7042 

To find the number corresponding to a given logarithm: 
As the mantissa of the given logarithm is not usually found 
in the table, select the four figures corresponding nearest to 
the given mantissa. The first two figures of the number 
will be found in the column marked "No." at the left of 
the row in which is the mantissa elected, and the third or 
last figure of the number at the top or bottom of the ver- 
tical row of figures. 

Example: Find the number from Table No. 2 corres- 
ponding to logarithm 1.0334. 



36 MACHINE SHOP PRACTICE 

Answer: The first two figures of the number corres- 
ponding to the mantissa .0334 are 10, and at the top of the 
vertical column the third figures given as 8, making the 
three figures 108. As the characteristic is 1 therefore the 

actual number is 10.8. 

t 

The number corresponding to ■ — 1.0334 is .108 
The number corresponding to 0.0334 is 1.08 
The number corresponding to 1.0334 is 10.8 
The number corresponding to 2.0334 is 108 

To multiply one or more numbers together, add the com- 
mon logarithms of the numbers together, the sum will be 
the logarithm of the required number. 

To divide a number by one or more numbers, subtract the 
sum of the common logarithms of the numbers from the 
logarithms of the number to be divided. 

The mantissa of the common logarithm of 6 is the same 
as the mantissa of 60 or 600, the characteristic only being 
changed thus: 

Common logarithm of .600 = — 1.7782 
Common logarithm of 6.00 = 0.7782 
Common logarithm of 60.0 = 1.7782 
Common logarithm of 600 = 2.7782 

Table No. 2 gives the common logarithms of numbers 
from 100 to 999. 

Note. A decimal point must always be prefixed to the 
mantissa of a logarithm obtained from the table, before 
affixing the characteristic. 



ARITHMETIC 



37 



Table No. 2. 
Logarithms of Numbers from 100 to 999. 


No. 





1 


2 


3 


4 


5 


6 


7 


8 


9 


Diff. 
40 

37 
33 
31 

29 

27 
25 

24 
23 
21 

21 

20 
19 
18 

17 
17 
16 

16 
15 
14 

14 

13 
13 
13 


10 

11 
12 
13 

14 
15 
16 

17 
18 
19 

20 

21 

22 
23 

24 

25 
26 

27 
28 
29 

30 

31 
32 
33 


0000 

0414 
0792 
1139 

1561 
1761 
2041 

2304 
2553 

2788 

3010 

3222 
3424 
3617 

3802 
3979 
4150 

4314 
4472 
4624 

4771 

4914 
5051 
5185 


0043 

0453 

0828 
1173 

1492 
1790 
2068 

2330 

2577 
2810 

3032 

3243 
3444 
3636 

3820 
3997 
4166 

4330 
4487 
4639 

4786 

4928 
5065 
5198 


0086 

0492 
0865 
1206 

1523 
1818 
2095 

2355 
2601 
2833 

3054 

3263 
3464 
3655 

3838 
4014 
4183 

4346 
4502 
4654 

4800 

4942 
5079 
5211 


0128 

0531 
0899 
1239 

1553 
1847 
2122 

2380 
2625 
2856 

3075 

3284 
3483 
3674 

3856 
4031 
4200 

4362 
4518 
4669 

4814 

4955 
5092 
5224 


0170 

0569 
0934 
1271 

1548 
1875 
2148 

2405 
2648 
2878 

3096 

3304 
3502 
3692 

3874 
4048 
4216 

4378 
4533 
4683 

4829 

4969 
5105 
5237 


0212 

0607 
0969 
1303 

1614 
1903 
2175 

2430 

2672 
2900 

3118 

3324 
3522 
3711 

3892 
4065 
4232 

4393 
4548 
4698 

4843 

4983 
5119 
5250 


0253 

0645 
1004 
1335 

1644 
1931 
2201 

2455 
2695 
2923 

3139 

3345 
3541 
3729 

3909 
4082 
4249 

4409 
4564 
4713 

4857 

4997 
5132 
5263 


0294 

0682 
1038 
1367 

1673 
1959 

2227 

2480 
2718 
2459 

3160 

3365 
3460 
3747 

3927 
4099 
4265 

4425 
4579 

4728 

4871 

5011 
5145 
5276 


0334 

0719 
0172 
1399 

1703 
1987 
2253 

2504 
2742 
2967 

3181 

3385 
3579 
3766 

3945 
4116 
4281 

4440 
4594 
4742 

4886 

5024 
5159 

5289 


0374 

0755 
1106 
1430 

1732 
2014 

2279 

2529 
2765 
2989 

3201 

3404 
3598 
3784 

3962 
4133 
4298 

4456 
4609 
4757 

4900 

5038 
5172 
5302 


No. 





1 


2 


3 


4 


5 


6 


7 


8 


9 



38 



MACHINE SHOP PRACTICE 



Table No. 2— Continued. 
Logarithms of Numbers from 100 to 999. 


No. 





1 


2 


3 


4 


5 


6 


7 


8 


9 


Diff. 

13 
12 
12 

12 
12 
12 

11 

10 
10 
10 

10 

10 

9 

9 
9 
9 

9 

8 
8 
8 

8 
8 
8 

Diff. 


34 
35 
36 

37 
38 
39 

40 

41 
42 
43 

44 
45 
46 

47 

48 
49 

50 

51 
52 
53 

54 
55 
56 


5315 
5441 
5563 

5682 
5798 
5911 

6021 

6128 
6232 
6335 

6435 
6532 
6628 

6721 
6812 
6902 

6990 

7076 
7X60 
7243 

7324 
7404 

7482 


5328 
5453 
5575 

5694 
5809 
5922 

6031 

6138 
6234 
6345 

6444 
6542 
6637 

6730 
6821 
6911 

6998 

7084 
7186 
7251 

7332 
7412 
7490 


5340 
5465 

5587 

5705 
5821 
5933 

6042 

6149 
6253 
6355 

6454 
6551 
6646 

6739 
6830 
6920 

6007 

7093 
7177 
7259 

7340 
7419 
7497 


5353 
5478 
5599 

5717 
5832 
5944 

6053 

6160 
6263 
6365 

6464 
6561 
6656 

6749 
6839 
6928 

7016 

7101 
7185 
7267 

7348 

7427 
7505 


5366 
5490 
5611 

5729 
5843 
5955 

6064 

6170 
6274 
6375 

6474 
6571 
6665 

6758 
6848 
6937 

7024 

7110 
7193 

7275 

7356 
7435 
7512 


5378 
5502 
5623 

5740 
5855 
5966 

6075 

6180 
6284 
6385 

6484 
6580 
6675 

6767 
6857 
6946 

7033 

7118 

7202 
7284 

7364 
7443 

7520 


5391 
5514 
5635 

5752 
5866 
5977 

6085 

6191 
6294 
6395 

6493 
6590 
6684 

6776 
6866 
6955 

7042 

7126 
7210 

7292 

7372 
7451 

7528 


5403 
5527 
5647 

5763 

5877 
5988 

6096 

6201 
6304 
6405 

6503 
6599 
6693 

6785 
6875 
6964 

7050 

7135 

7218 
7300 

7380 
7459 
7536 


5416 
5539 
5658 

5775 
5888 
5999 

6107 

6212 
6314 
6415 

6513 
6609 
6702 

6794 
6884 
6972 

7059 

7143 
7226 
7308 

7388 
7466 
7543 


5428 
5551 
5670 

5786 
5899 
6010 

6117 

6222 
6325 
6425 

6522 
6618 
6712 

6803 
6893 
6981 

7067 

7152 
7235 
7316 

7396 

7474 
7551 


No. 





1 


2 


3 


4 


5 


6 


7 


8 


9 



ARITHMETIC 



39 



Table No. 2— Continued. 
Logarithms of Numbers from 100 to 999. 


No. 





1 


2 


3 


4 


5 


6 


7 


8 


9 


Diff. 

7 
8 
8 

7 

7 
6 

7 

7 
6 
7 

6 
6 
6 

7 

6 
6 
6 

6 
6 
6 

6 
5 
6 

Diff. 


57 
58 
59 

60 

61 
62 
63 

64 
65 
66 

67 
68 
69 

70 

71 
72 
73 

74 
75 
76 

77 
78 
79 


7559 
7634 
7709 

7782 

7853 
7924 
7993 

8062 
8129 
8195 

8261 
8325 
8388 

8451 

8513 
8573 
8633 

8692 
8751 
8808 

8865 
8921 
8976 


7566 
7642 

7716 

7789 

7860 
7931 
8000 

8069 
8136 
8202 

8267 
8331 
8395 

8457 

8519 
8579 
8639 

8698 
8756 
8814 

8871 
8927 
8982 


7574 
7649 
7723 

7796 

7868 
7938 
8007 

8075 
8142 
8209 

8274 
8338 
8401 

8463 

8525 
8585 
8645 

8704 
8762 
8820 

8876 
8932 
8987 


7582 
7657 
7731 

7803 

7875 
7945 
8014 

8082 
8149 
8215 

8280 
8334 
8407 

8470 

8531 
8591 
8651 

8710 
8768 
8825 

8882 
8938 
8993 


7589 
7664 
7738 

7710 

7882 
7952 
8021 

8089 
8156 
8222 

8287 
8351 
8414 

8476 

8537 
8597 
8657 

8716 
8774 
8831 

8887 
8943 
8998 


7597 
7672 
7745 

7818 

7889 
7959 
8028 

8096 
8162 
8228 

8293 
8357 
8420 

8482 

8543 
8503 
8663 

8722 
8779 
8837 

8893 
8949 
9004 


7604 
7679 
7752 

7825 

7896 
7966 
8035 

8102 
8169 
8235 

8299 
8363 
8426 

8488 

8549 
8609 
8669 

8727 
8785 
8842 

8899 
8954 
9009 


7612 
7686 
7760 

7832 

7903 
7973 
8041 

8109 
8176 
8241 

8300 
8370 
8432 

8494 

8555 
8615 
8675 

8733 
8791 
8848 

8904 
8960 
9015 


7619 
7694 
7767 

7839 

7910 
7980 
8048 

8116 
8182 
8248 

8312 
83 7G 
8439 

8500 

8561 
8621 
8681 

8739 
8797 
8854 

8910 
8965 
9020 


7627 
7701 

7774 

7846 

7917 
7987 
8055 

8122 
8189 
8254 

8319 
8382 
8445 

8506 

8567 
8627 
8686 

8745 
8802 
8859 

8915 
8971 
9025 


No. 





1 


2 


3 


4 


5 


6 


7 


8 


9 



40 



MACHINE SHOP PRACTICE 



Table No. 2— Continued. 
Logarithms of Numbers from 100 to 999. 


No. 





1 


2 


3 


4 


5 


6 


7 


8 


9 


Diff. 

6 

5 
5 
5 

5 
5 
5 

5 
5 

4 

4 

5 
5 
4 

4 
5 
5 

4 
4 
4 

Diff. 


80 

81 

82 
83 

84 
85 
86 

87 
88 
89 

90 

91 
92 
93 

94 
95 
96 

97 

98 
99 


9031 

9085 
9138 
9191 

9243 
9294 
9345 

9395 
9445 
9494 

9542 

9590 
9638 
9685 

9731 

9777 
9823 

9868 
9912 
9956 


9036 

9090 
9143 
9196 

9248 
9299 
9350 

9400 
9450 
9499 

9547 

9595 
9643 
9689 

9736 

9782 
9827 

9872 
9917 
9961 


9042 

9096 
9149 
9201 

9253 
9304 
9355 

9405 
9455 
9504 

9552 

9600 
9647 
9694 

9741 
9786 
9832 

9877 
9921 
9965 


9047 

9101 
9154 
9206 

9258 
9309 
9460 

9410 
9460 
9509 

9557 

9605 
9652 
9699 

9745 
9790 
9836 

9881 
9926 
9969 


9053 

9106 
9159 
9212 

9263 
9315 
9465 

9415 
9465 
9513 

9562 

9609 
9657 
9603 

9750 
9795 
9841 

9886 
9930 
9974 


9058 

9112 
9165 

9217 

9269 
9320 
9469 

9420 
9469 
9518 

9566 

9614 
9661 
9701 

9754 
9800 
9845 

9890 
9934 
9978 


9063 

9117 
9170 
9222 

9274 
9325 
9474 

9425 
9474 
9523 

9571 

9619 
9666 
9713 

9759 
9805 
9850 

9894 
9939 
9983 


9069 

9122 
9175 

9227 

9279 
9330 
9479 

9430 
9479 
9528 

9576 

9624 
9671 
9717 

9763 
9809 
9854 

9899 
9943 
9987 


9074 9079 

9128 9133 
9180 9186 
9232 9238 

9284 9289 
9335 9340 
9484 9489 

9435 9440 
9484 9489 
9533 9538 

9581 9586 

9628 9633 
9675 9680 
9722 9724 

i 
9768 9773 
9814 9818 
9859 9863 

9903 9908 
9948 9952 
9991 9996 

1 


No. 





1 


2 


3 


4 


5 


6 


7 


8 


9 



PRACTICAL GEOMETRY 



PRACTICAL GEOMETRY. 

To bisect a straight line— Fig. 1. Let BC be the straight 
/ine to be bisected. With any convenient radius greater 
than AB or AC describe arcs cutting each other at D and 
E. A line drawn through D and E will bisect or divide 
the line BC into two equal parts. 



B' 



:e 

Fig. 1. 




Fig. 2. 



To erect a perpendicular line at or near the end of a 
straight line— Fig 2. With any convenient radius and at 
any distance from the line AC, describe an arc of a circle 
as ACE, cutting the line at A and C. Through the center 
R of the circle draw the line ARE, cutting the arc at point 
E. A line drawn from C to E will be the required per- 
pendicular. 

To divide a straight line into any number of equal parts 
—Fig. 3. Let AB be the straight line to be divided into a 
certain number of equal parts: From the points A and B, 
draw two parallel lines AD and BC, at any convenient 
angle with the line AB. Upon AD and BC set off one less 
than the number of equal parts required, as A-l, 1-2, 2-D, 
etc. Join C-l, 2-2, 1-D, the line AB will then be divided 
into the required number of equal parts. 

To find the length of an arc of a circle— Fig. 4. Divide 
the chord AC of the arc into four equal parts as shown. 

43 



44 



MACHINE SHOP PRACTICE 




Fig. 3. 




With the radius AD equal to one-fourth of the chord of the 
arc and with A as the center describe the arc DE. Draw 
the line EG and twice its length will be the length of the 
arc AEC. . 

To draw radial lines from the circumference of a circle 
when the center is inaccessible— Fig. 5. Divide the circum- 
ference into any desired number of parts as AB, BC, CD, 
DE. Then with a radius greater than the length of one 




Fig. 5. 



part, describe arcs cutting each other as A-2, C-2, B-3, D-3, 
etc, also B-l, D-5. Describe the end arcs A-l, E-5 with a 
radius equal to B-2. Lines joining A-l, B-2, C-3, D-4 and 
E-5 will all be radial. 

To inscribe any regular polygon in a circle— Fig. 6. 
Divide the diameter AB of the circle into as many equal 
parts as the polygon is to have sides. With the points A 
and B as centers and radius AB, describe arcs cutting each 
other at C. Draw the line CE through the second point of 



PRACTICAL GEOMETRY 



45 



division of the diameter 
of AB, intersecting the 
circumference of the circle 
D. A line drawn from B 
to D is one of the sides of 
the polygon. 




To cut a beam of the 
strongest shape from a 
circular section— Fig. 7. 
Divide any diameter CB 
of the circle into three 
equal parts as CF, FE and 
EB. At E and F erect 
perpendiculars EA and FD 
on opposite sides of the 
diameter CB. Join AB, 
BD, DC and CF. The rect- 
angle ABCD will be the 
required shape of the beam. 




Fig. 8. 



46 



MACHINE. SHOP PRACTICE 



To develop the surface of a cone or the frustum of a 
cone— Fig. 8. Let ABC represent the cone and DEAB the 
frustum of the cone. On the base AB of the cone describe 
the semicircle AFB. With C as a center and radius CB, 
describe the arc BG. Make BG equal to twice the length 
of AFB and join CG. The sector CBG will be required 
surface of the cone. With center C and radius CE draw 
the arc EH, intersecting the line CG at H. The shape 
EHBG will be the required surface of the frustum of the 
cone. 

To construct a square upon 
a straight line of given length 
—Fig. 9. With A and C as 
centers and radius AC, de- 
scribe the arcs AF and AE, 
cutting each other at D. 
With center D and radius AC 
describe the circle ACEHGF 
and with the same radius and 
centers E and F, describe 
the arcs EH, FG. Draw the 
lines AG, CH and KL, which 
completes the square required. 

To construct a square equal in area to a given triangle 
—Fig. 10. Let ABC be the given triangle: Let fall the 
perpendicular BD, produce the line CA at A and make AE 
equal to half the perpendicular height BD. Bisect CE at F 

and describe the semicircle ^ B~""\G H 

CGE. Erect the perpen- 
dicular, AG at G and this 
will be one of the sides 
of the required square 
AGHM. 





PRACTICAL GEOMETRY 



47 



To construct a square equal in area to a given rectangle 
—Fig. 11. Produce the base AB of the rectangle ABGH at 
A and make AC equal to AG. Bisect CB and D and de- 
scribe the semicircle AEB. Produce the line AG until it 
intersects the circumference of the semicircle at E, then 
[A.E is one side of the required square AELK. 



1 


G 


\h 




K 


C / 


\ D 

Fig. 11. 


B 




Fig. 12. 

To find the length of a rectangle equal in area to a given 
square when the width of the rectangle is given— Fig. 12. 
Let ABCD be the given square and DE the width of the 
rectangle whose length is required. From E draw EH par- 
allel to DC and produce DC to G and BC to F. Join DF 
and draw AG parallel to DF, cutting DC produced at G. 
Draw GH parallel to DE and DEGH is the required rect- 
angle. 

To divide any triangle into two parts of equal area— 
Fig. 13. Let ABC be the given triangle: Bisect one of its 
sides AB at D and describe the semicircle AEB. At D 
erect the perpendicular DE and with center B and radius 



48 



MACHINE SHOP PRACTICE 



BE describe the are EF which intersects the line AB at F. 
At F draw the line AG parallel at AC, this divides the tri- 
angle into two parts of equal area. 

A, 





Fig. 14. 

To inscribe a circle of the greatest possible diameter in a 
given triangle— Fig. 14. Bisect the angles A and B, and 
draw the lines AD, BD which intersect each other at D. 
From D draw the line CD perpendicu- 
lar to AB. Then CB will be the radius 
of the required circle CEF. 

To construct a rectangle of the great- 
est possible area in a given triangle— 
Fig. 15. Let ABC be the given triangle : 
Bisect the sides AB and BC at G and 
F. Draw the line GD and from the 
points G and D, draw the lines GF and 
DE perpendicular to GD, then EFGD 
is the required rectangle. 




PRACTICAL GEOMETRY 



49 



To construct a rectangle equal in area to a given triangle 
—Fig. 16. Let ABC be the given triangle: Bisect the base 
E C F AB of the triangle at D 

and erect the perpendicu- 
lars DE and BF at D and B. 
Through C draw the line 
ECF intersecting the per- 
pendiculars DE and BE at 
E and F. Then BDEF is 
the required rectangle. 

To construct a triangle equal in area to a given parallel- 
ogram—Fig. 17. Let 
ABCD be the given par- 
allelogram: Produce the 
line AB at B and make 
BE equal to AB. Joint 
the points A and C and 
ACE will be the triangle 
required. 





To 
Fig. 
H 



18. Let ACBD be the given circle 



construct a square equal in area to a given circle— 

Draw the dia- 
meters AB and CD at right an- 
gles to each other, then bisect 
the half diameter or radius 
DB at E and draw the line 
CEF also from the point F 
draw the line FL, parallel to 
BA. At the points C and 
F erect the perpendiculars 
CHand FG, equal in length 
to CF. Join HG, then CFGH 
is the required square. The 
dotted line FL is equal to 
one-fourth the circle ACBD. 




50 



MACHINE SHOP PRACTICE 



To inscribe a square within a given circle— Fig. 19. Let 
ADBC be the given circle: Draw the diameters AB and 
CD at right angles to each other. Join AD, DB and CA, 
then ACBD is the inscribed square. 




E A 

C 



Fig. 19. 



B 

Fig. 20. 



H 



To describe a square without a given circle— Fig. 20. 
Draw the diameters AB and CD at right angles to each 
other. Through A and B draw the lines EF and GH, par- 
allel to CD, also draw the lines EG and FH through the 
points C and D and parallel to AB, this completes the re- 
quired square EFGH. 



To construct an octagon in 
a given square— Fig. 21. Let 
ABCD be the given square: 
Draw the diagonal lines AC 
and BD,which intersect each 
other at the point 0. With 
a radius equal to AO or OC, 
describe the arcs EF,GH, IK 
and LM. Connect the points 
EK, LG, FI and HM, then 
GFIHMKEL is the required 
octagon. 




PRACTICAL GEOMETRY 



51 



To describe an octagon about a given circle— Fig. 22. Let 
ACBD be the given circle : Draw the diameters AB and 
CD at right angles to each other. With any convenient 
radius and centers A, C, B and D describe arcs intersecting 
each other at E, H, F and G. Join EF and GH which form 
two additional diameters. At the points AB and CD draw 
the lines KL, PR, MX and ST, parallel with the diameters 
CD and AB respectively. At the points of intersection of 
the circumference of the circle by the lines EF and GH, 
draw the lines KP. RM, NT and SL parallel with the lines 
EF and HG respectively, then PRMNTSLK is the required 
octagon. 





Fig. 23. 



To construct a circle equal in area to two given circles 
—Fig. 23. Let AB and AC equal the diameters of the 
given circles: Erect AC at A and at right angles to AB. 
Connect B and C, then bisect the line BC at D and describe 
the circle ACB which is the circle required and is equal 
in area to the two given circles. 



52 



MACHINE SHOP PRACTICE 



To construct a square equal in area to two given squares 
—Fig. 24. Let AC and AD be the length of the sides of 
the given squares : Make AD perpendicular to AC and con- 
nect DC, then DC is one of the sides of the square DCEG 
which is equal to the two given squares. 




To draw a straight line equal in length to a given por- 
tion of the circumference of a circle— Fig. 25. Let ACBD 

be the given circle: Draw the diameters AB and CD at 
right angles with each other. Divide the radius RB into 
four equal parts. Produce the diameter AB at B and make 
BE equal to three of the four parts of RB. At A draw the 
line AF parallel to CD and then draw the line ECF which 
is to one-fourth of the circumference of the circle ACBD. 
If lines be drawn from E through points in the circumfer- 
ence of the circle as 1 and 2, meeting the line AF at G and 
H, then C-l, 1-2 and 2-A will equal FG, GH and HA re- 
spectively. 



PRACTICAL GEOMETRY 



53 



To inscribe a hexagon in a given circle— Fig. 26. Draw 
a diameter of the circle as AB: With centers A and B 
and radius AC or BG, describe arcs cutting the circum- 
ference of the circle at D, E, F and G. Join EF, FB, BG, 
GD, DA and AE, this gives the required hexagon. 

D 




Fig. 26. 

To find the correct position of an eccentric in relation to 
the crank, the travel of the slide valve being given— Fig. 27. 
Draw the line AB equal to the travel of the valve and with 
center G describe a circle ADBC. The line AG represents 
the position of the crank at the beginning of the piston 
stroke. Draw the diameter CD perpendicular to AB, then 
draw the line EF, which should be equal to the sum of the 
lap and lead of the valve. Connect EG and FG, and E 
will be correct position for the forward eccentric and F the 
correct position for the backward eccentric. 

To lay out the throw of an 
eccentric for operating a slide- 
valve— Fig. 28. The throw of 
an eccentric is equal to the 
distance between the center of 
the shaft and the center of 
the eccentric, as at AB. The 
travel of the valve necessary 
to open the port its full width, 
is equal to^wice the sum of 
the width of the port and the 
lap of the valve. 




Fig. 28. 



54 



MACHINE SHOP PRACTICE 



To describe a cycloid, the diameter of the generating cir- 
cle being given— Fig. 29. Let BD be the generating circle: 
Draw the line ABC equal in length to the circumference of 
the generating circle. Divide the circumference of the gen- 
erating circle into 12 parts as shown. Draw lines from the 
points of division, 1, 2, 3, etc., of the circumference of the 
generating circle parallel to the line ABC and on both sides 
of the circle. Lay off one division of the generating circle 
on the lines 5 and 7, two divisions on the lines 4 and 8, 
three divisions on the lines 3 and 9, four divisions on the 
lines 2 and 10, and five divisions on the lines 1 and 11. A 
line traced through the points thus obtained will be the 
cycloid curve required. 




To develop a spiral with uniform spacing— Pig. 30. 

Divide the line BE into as many equal parts as there are 
required turns in the spiral. Then subdivide one of these 
spaces into four equal parts. Produce the line BE to 4, 
making the extension E-4 equal to two of the subdivisions. 
At 1 draw the line 1-D, lay off 1-2 equal to one of the sub- 
divisions. At 2 draw 2-A perpendicular to 1-D and at 3 in 
2-A draw 3-C, etc. With center 1 and raduis 1-B describe 
the arc BD, with center 2 and radius 2-D describe the arc 
DA, with center 3 and radius 3-A, etc. until the spiral is 



PRACTICAL GEOMETRY 



55 



completed. If carefully laid out the spiral should terminate 
at E as shown in the drawing. 





A EC 

Fig. 31. 

To bisect a given angle, 
that is to divide it into two 
equal parts— Fig. 31. Let 
CAD be the angle to be bi- 
sected. With any convenient 
Fi s- 30 - radius describe equal arcs, 

cutting AC and AD in E and G respectively. With the 
points E and C as centers and with any radius greater than 
EG, describe equal arcs intersecting each other at H. Join 
the points and H and the angle CAD is bisected as required. 
To construct a 90° angle or a right- angle— Fig. 32. Draw 
the line AC of any convenient length and on AC mark off 
any distance AE. With centers A and E and radius AE, 
describe arcs cutting at F and with F as a center and ra- 
dius FA describe the arcs AGD. With radius FA mark off 
the distances AG and GD on the arc AGD. Join the points 
D and A and the angle DAC is equal to 90°. 

D , D 




% 



Fig. 32, 



i 




A E 1 C 

To construct a 60° angle— Fig. 33. 

before and mark off the distance AE. 



E' 
Fig. 33. 

Draw the line AC as 
With centers A and 



56 



MACHINE SHOP PRACTICE 



E and radius AE, describe arcs cutting at G. Draw the 
line AD from the point G through C and DAC is the re- 
quired 60° angle. 

To construct a 45° angle— Fig. 34. Upon the line AC 
locate the point E, at any suitable distance from A. With 
centers A and E and radius AE, describe arcs cutting each 
other at F. Draw the line EFG and make the distance FG, 
equal to FE. Join the points AG, and on the line AG lay 
off AH equal to AE. With any suitable radius greater 
than the distance EH, and with centers E and H, describe 
arcs cutting each other in L. The line AD drawn from the 
point A through L completes the 45° angle. 





To construct a 30° angle— Fig. 35. Draw the line AC 
and mark off any distance AE, with centers A and E and 
radius AE describe arcs cutting each other at G. With any 
radius greater than the distance EG and with centers E and 
G describe arcs cutting each other at D, draw the line AD 
and this completes the 30° angle required. 



MENSURATION 



MENSURATION OF PLANE 

To find the area of a circle— Fig. 36. 
of the diameter by .7854. 

To find the circumference of a circle, 
meter by 3.1416. 

Circle: Area = .7854D 2 
Circ. = 3.1416D 



SURFACES. 

Multiply the square 

Multiply the dia- 





Fig. 36. 

To find the area of a semi-circle— Fig. 37. Multiply the 
square of the diameter by .3927. 

To find the circumference of a semi-circle. Multiply the 
diameter by 2.5708. 

Semi-circle: Area = .3927D 2 
Circ. = 2.5708D 

To find the area of an annular ring— Fig. 38. From 
the area of the outer circle subtract the area of the inner 
circle, the result will be the area of the annular ring. 



To find the outer circumference of an annular ring, 
tiply the outer diameter by 3.1416. 

59 



Mul. 



60 



MACHINE SHOP PKACTICE 



To find the inner circumference of an annular ring. Mul- 
tiply the inner diameter by 3.1416. 
Annular ring: Area = .7854 (D 2 — H 2 ) 

Out. circ. = 3.1416 D 
Inn. circ. = 3.1416 H 





Fig. 39. 

To find the area of an ellipse.— Fig. 39. Multiply the long 
diameter by the short diameter and by .7854. 

To find the area of a flat-oval— Fig. 40. Multiply the 
sum of the long and short distance by 1.5708. 

Ellipse: Area=.7854 (D><H) 
Circ.=1.5708 (DXH) 

To find the area of a flat-oval— Fig. 40. Multiply the 
length by the width and substract .214 times the square 
of the width from the result. 

To find the circumference of a flat-oval. The circumfer- 
ence of a flat-oval is equal to twice its length plus 1.142 
times its width. 



Flat-oval : Area = D (H— 0.214D ) D 
Circ.=2 (HX0.571D) j 



U H 

Fig. 40. 



MENSURATION 



61 



To find the area of a parabola— Fig. 41. Multiply the 

base by the height and by .667. 
Parabola: Area = .667 (DXH) 




D — 

Fig. 42. 

To find the area of a square— Fig. 42. Multiply the 
length by the width or in other words the area is equal to 
square of the diameter. 

To find the circumference of a square. The circumfer- 
ence of a square is equal to the sum of the lengths of the 
sides. 

Square: Area = D 2 

Circ. = 4D 

To find the area of a rectangle— Fig. 43. Multiply the 
length by the width, the result is the area of the rectangle. 

To find the circumference of a rectangle. The circum- 
ference of a rectangle is equal to twice the sum of the 
length and width. 

Rectangle: Area = DXH. 
Circ. = 2 (DXH) 





I 

|^ D ->1 

Fig. 44. 

To find the area of a parallelogram— Fig. 44. Multiply 



62 



MACHINE SHOP PRACTICE 



the base by the perpendicular height. 
Parallelogram : Area = DXH 

To find the area of a trapezoid— Fig. 45. Multiply half 
the sum of the two parallel sides by the perpendicular dis- 
tance between the sides. 

(H E+D) 
2 



Trapezoid: Area= 



E->1 





D »1 

Fig. 46. 

To find the area of an equilateral triangle— Fig. 46. The 

area of an equilateral triangle is equal to the square of one 
side multipled by .433. 

To find the circumference of an equilateral triangle. The 
circumference of an equilateral triangle is equal to the sum 
of the length of the sides. 
Equilateral triangle: Area — .433D 2 
Circ. = 3D 

r 




To find the area of a right-angle or an isosceles triangle 
—Fig. 47. Multiply the base by half the perpendicular 
height. 



MENSURATION 



63 



To find the circumference of a right-angle or an isosceles 
triangle : 
Right angle or isosceles triangle: 

DXH 
Area= — - — 



Circ.=i/(4H 2 +D 2 )+D 

To find the area of an hexagon— Fig. 48. Multiply the 
square of one side by 2.598. 

To find the circumference of a hexagon: The circumfer- 
ence of a hexagon is equal to the sum of the length of the 
sides. 

Hexagon: Area = 2.598S 2 
Circ. = 6S 
D = 1.732 1 S 



r 

i 

(/) 

I 

1. 



U D — >i U ^-D -J 

Fig. 48. Fig. 49. 

To find the area of an octagon— Fig. 49. Multiply the 
square of the short diameter by .828. 

To find the circumference of an octagon. The circumfer- 
ence of an octagon is equal to the sum of the length of the 
sides. 

Octagon: Area = .828D 2 
Circ. e= 8S 
S = .414D 

To find the area of any regular polygon— Fig. 50. Multi- 
ply half the sum of the sides by the perpendicular distance 
from the center of one of the sides. 



64 



MACHINE SHOP PRACTICE 



To find the circumference of any regular polygon. The 

circumference of any polygon is equal to the sum of the 
length of the sides. 



Polygon : Area = 



No. of sidesXDXP 



Circ. e= No. of sidesXD 
D = Length of one side. 
P = Perpendicular distance 

from the center to 

one side. 




MENSURATION OF VOLUME AND SURFACE OF 
SOLIDS. 



To find the cubic contents of a sphere 
the cubic of the diameter by .5236. 

To find the superficial area of a sphere, 
square of the diameter by 3.1416. 
Sphere. Cubic contents=.5236D 3 

Superficial area t= 3.1416D 2 



D 



Fig. 51. Multiply 
Multiply the 





Fig. 52. 
k D -J 

Fig. 51. 

To find the cubic contents of a hemisphere- 

Multiply the cube of the diameter by .2618. 



Fig. B2. 



MENSURATION 



65 



To find the superficial area of a hemisphere. 
Hemisphere: Cubic contents — .2618D 2 

Superficial area == 2.3562D 2 

To find the cubic contents of a cylindrical ring— Fig. 53. 
To the cross-sectional diameter of the ring add the inner 
diameter of the ring, multiply the sum by the square of the 
cross-sectional diameter of the ring and by 2.4674, the pro- 
duct is the cubic contents. 

To find the superficial area of a cylindrical ring. To the 
cross-sectional diameter of the ring add the inner diameter 
of the ring. Multiply the sum by the cross-sectional dia- 
meter of the ring and by 9.8696, the product is the superfi- 
cial area. 

Cylindrical Ring: Cubic contents=2.4674T 2 (T-fH) 
Superficial area=9.8696T(T+H) 
D=(H+2T) 





Fig. 54. 

To find the cubic contents of a cylinder— Fig. 54. Multi- 
ply the area of one end by the length of the cylinder, the 
product will be the cubic contents of the cylinder. 

To find the superficial area of a cylinder. Multiply the 
circumference of one end by the length of the cylinder and 
add to the product the area of both ends. 



66 



MACHINE SHOP PRACTICE 



Cylinder: Cubic contents=.7854(D+H) 

Superficial area=1.5708D(2!H-t-D) 

To find the cubic contents of a cone— Fig. 55. Multiply 
the square of the base by the perpendicular height and by 
.2618. 

To find the superficial area of a cone. Multiply the cir- 
cumference of the base by one-half the slant height and 
add to the product the area of the base. 
Cone: Cubic contents = .2618 (D 2 XH) 
Superficial area=.7854D(2S+D) 




l<~E 




To find the cubic contents of the frustum of a cone— Pig, 

56. To the sum of the areas of the two ends of the frus- 
tum, add the square root of the product of the diameters of 
the two ends, this result multiplied by one-third of the per- 
pendicular height of the frustum will give the cubic con- 
tents. 

To find the superficial area of the surface of the frustum 
of a cone. Multiply the sum of the diameters of the ends 
by 3.1416 and by half the slant height. Add to the result 
the area of both ends and the sum of the two will be super- 
ficial area. 



MENSURATION 



67 



Frustum of cone: 



Cubic contents= 



H(.2618( E 2 +D 2 )i/EXD) 



Superficial area=3.1416S (^r^) +.7854(E 2 +D 2 ) 



^m 



+H 2 



To find the contents of a cube— Fig. 57. The contents of 
equal to the cube of its diameter. 

To find the superficial area of a cube. The superficial 
area of a cube is equal to six times the square of its dia- 
meter. 
Cube: Cubic contents = D 3 

Superficial area = 6D 2 




Fig. 58. 



k- D- 

U D V 

Fig. 57. 

To find the cubic contents of a rectangle solid— Fig. 58. 

Multiplying together the length, width and height will give 
the cubic contents of the rectangular solid. 

To find the superfiicial area of a rectangular solid. Mul- 
tiply the width by the sum of the height and length and 
add to it the product of the height multiplied by the length, 
twice this sum is the superficial area of the rectangular 
solid- 



68 MACHINE SHOP PRACTICE 

Rectangular solid: 

Cubic contents = DXHXL 
Superficial area=2(D(H+L)+HL) 

To find the cubic contents of a pyramid— Fig. 59. Multi- 
ply the area of the base by one-third the perpendicular 
height and the product will be the cubic contents of the 
pyramid. 

To find the superficial area of a pyramid. Multiply the 
circumference of the base by half the slant height and to 
this add the area of the base, the sum will be the superfi- 
cial area. 

D 2 XH 



Pyramid: Cubic contents^ 



Superficial area = ( — h4D 



-v? 



Vh 2 




MENSURATION OF TRIANGLES. 

To find the base of a right-angle triangle when the per- 
pendicular and the hypothenuse are given— Fig. 60. Sub- 
tract the square of the perpendicular from the square of the 
hypothenuse, the square root of the difference is equal to 
the length of the base. 



Base=i/Hypotenuse 2 — Perpendicular 2 or B=i/C 2 — H 2 

To find the perpendicular of a right-angle triangle when 
the base and hypothenuse are given. Subtract the square of 
the base from the square of the hypothenuse, the square 



MENSURATION 



69 



root of the difference is equal to the length of the perpen- 
dicular. 



Perpendicular=i/Hypotenuse 2 — Base 2 or H=i/C 2 — B 2 

To find the hypothenuse of a right-angle triangle when 
the base and the perpendicular are given. The square root 
of the sum of the squares of the base and the perpendicu- 
lar is equal to the length of the hypothenuse. 



Hypotenuse=i/Base 2 +Perpendicular 2 
C=i/B 8 +H 8 ' 





Fig. 60. 

To find the perpendicular height of any oblique angled 
triangle— Fig. 61. From half the sum of the three sides of 
the triangle, subtract each side severally. Multiply the 
half sum and the three remainders together and twice the 
square root of the result divided by the base of the triangle 
will be the height of the perpendicular. 



2i/S(S— A) (S— B) (S— C) 



S= 



Sum of sides 



To find the area of any oblique angled triangle when only 
the three sides are given. From half the sum of the three 



70 



MACHINE SHOP PRACTICE 



sides, substract each side severally. Multiply the half sum 
and the three remainders together and the square root of 
the product is equal to the area required. 



Area=i/S(S— A) (S— B) (S— C) 



To find the height of the perpendicular and the two sides 
of any triangle inscribed in a semi-circle, when the base of 
the triangle and the location of the perpendicular are given 
-Fig. 62. 




C 2 C 2 — 

A=~- B=^ C=i/AXB 
B A 



D=t/A(A+B) E=i/B(A+B) 



PROPERTIES OF THE CIRCLE. 

A circle contains a greater area than any other plane 
figure bounded by the same length of circumference or out- 
line. 

The areas of circles are to each other as the squares of 
their diameters. Any circle twice the diameter of another 
contains four times the area of the other. 



MENSURATION 



71 




The radius of a circle is a straight line drawn from the 
centre to the circumference as LM— Fig. 63. 

The diameter of a circle is a 
straight line drawn through 
the centre, and terminated 
both ways at the circumfer- 
ence, as ALC. 

A chord is a straight line aJ 
joining any two points of the 
circumference, as DE. 

The versed sine is a per- 
pendicular joining the middle 
of the chord and circumfer- 
ence, as GH. 

An arc is any part of the circumference, as DHE. 

A semicircle is half the circumference cut off by a dia- 
meter, as AHC. 

A segment is any portion of a circle cut off by a chord, 
as DHE. 

A sector is a part of a circle cut off by two radii, as 
ALM or CLM. 

Circumference. Multiply the diameter by 3.1416, the pro- 
duct is the circumference. 

Diameter. Multiply the circumference by .31831, the pro- 
duct is the diameter, or multiply the square root of the 
area by 1.12837, the product is the diameter. 

Area. Multiply the square of the diameter by .7854, the 
product is the area. 

Side of square. Multiply the diameter by .8862, the pro- 
duct is the side of a square of equal area. 

Diameter of circle. Multiply the side of a square by 
1.12&, the product is the diameter of a circle of equal area. 

To find the versed sine, chord of an arc or the radius 
when any two of the three factors are given— Fig. 64. 



72 



MACHINE SHOP PRACTICE 



. c — -- >, 




F c >i 




Fig. 65. 



R= 



C 2 +4V 2 



8V 
V=R- 



C=2v / V(2R— V) 



'4R 2 — C 2 



aR 



To find the length of any line perpendicular to the chord 
of an arc, when the distance of the line from the center of 
the chord, the radius of the arc and the length of the ver- 
sed sine are given— Fig. 65. 

■ C 2 +4V 2 

N=i/(R 2 — X 2 )— (R— H) 



R= 



8V 



C=2i/V(2R— V) 



V=K-V 4 -^ 



To find the diameter of a circle when the chord and ver- 



sed sine of the arc are given. 



AC= 



DG 2 +GH* 



GH 



To find the length of any arc of a circle, when the chord 
of the whole arc and the chord of half the arc are given 



-Fig. 66. 



Arc DHE= 



8DH—DE 




Fig. 66. 



MENSURATION 



73 



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1.7671 

4.9087 

9.6211 

15.9043 

23.7583 

33.1831 

44.1787 

5(5.7451 

70.8823 

86.5903 

108.8691 

122.7187 

143.1391 

165.1303 

188.(5923 

213.8251 

240.5287 

268.8031 

298.6483 


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1.5393 

4.5239 

9.0792 

15.2053 

22.9022 

32.1(599 

48.0085 

55.4178 

(59.3979 

84.9488 

102.0705 

120.7(531 

141.02(54 

1(52.8(505 

18(5. 2(554 

211.1411 

237.7877 

2(55.9050 

295.5931 


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1.3273 

4.1547 

8.5530 

14.5220 

22.0618 

31.1725 

41.8539 

54.10(52 

67.9292 

83.2320 

100.2877 

118.8231 

138.9294 

1(50.(5064 

L88.8542 

208.(5723 

235.0(523 

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74 



MACHINE SHOP PRACTICE 



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Mechanical Powers consist of simple mechanical devices 
whereby weights may be raised or resistances overcome 
with the exertion of less power than would be necessary 
without them. 

They are six in number: The lever, the wheel and pinion, 
the pulley, the inclined plane, the wedge, and the screw. 
Properly two of these comprise the whole, namely, the 
lever and the inclined plane,— the wheel and pinion being 
only a lever of the first kind, and the pulley a lever of 
the second, the wedge and screw being also similarly allied 
to that of the inclined plane. Although such seems to be 
the case, yet they each require, on account of their various 
modifications, a different rule of calculation adapted ex- 
pressly to the different circumstances in which they are re- 
quired to act. 

The primary elements of machinery are therefore two 
only in number, the lever and the inclined plane. 

The Lever. 

Levers, according to the method of application, are of the 
first, second, or third kind. Although levers of equal lengths 
produce different effects, the general principles of estima- 
tion in all are the same, namely, the power is to the 
weight, as the distance of one end of the fulcrum is to the 
distance of the other end to the same point. 

In a lever of the first kind the fulcrum is between the 
power and the weight, as in Fig. 67. A pair of pliers or 
scissors are double levers of the first kind. 

In a lever of the second kind, the weight is between the 
power and the fulcrum, as in Fig. 68. A wheel-barrow, 
or the oars of a boat where the water is considered the 

85 



86 MACHINE SHOP PRACTICE 

fulcrum, and a door, represent levers of the second kind. 

In a lever of the third kind, the power is between the 
fulcrum and the weight, as in Fig. 69. Levers of the third 
kind are instruments such as tongs, shears, &c. 

In the first kind, the power is to the weight, as the dis- 
tance W F is to the distance F P. 

In the second, the power is 



w 




w F 



to the weight, as the distance 
F W is to that of F P;and, 

In the third, the weight is 1 A 

to the power, as the distance 
F P is to that of F W. 

To find the power. Multi- 
ply the weight by its distance 

from the fulcrum, and divide Fi s- 67 « 

by the distance of the power 
from the fulcrum. 

To find the weight. Mul- 
tiply the power by its distance 
from the fulcrum, and divide 
by the distance of the weight 
from the fulcrum. 

To find the distance of the 
power from the f ulcrum. Mul- Fig. 68. 

tiply the weight by its dis- 
tance from the fulcrum, and 
divide by the power. 

To find the distance of 
the weight from the fulcrum. 
Multiply the power by its 
distance from the fulcrum, 
and divide by the weight. 

Let P be the power, F the fulcrum and W the weight, 
then for a lever of the first kind. (Fig. 67.) 



p 




w 



F P 



S 



APPLIED MECHANICS 



87 



P=W 



FW 

FP 



W=P 



FP 
FW 



And for a lever of the second kind. (Fig 68.) 



FP FW 



And for a lever of the third kind. 

w=: 



p=w— 



(Fig. 69.) 
jp 

FW 



The Wheel and Pinion. 

The mechanical advantage of the wheel and pinion sys- 
tem, Fig. 70, is as the velocity of the weight to the velocity 
of the power, and being only a modification of the first 
kind of lever, it of course partakes of the same principles. 

To find the power.— Multiply the weight by the radius 
of the drum, and divide by the radius of the wheel. 

To find the radius of the wheel.— Multiply the weight by 
the radius of the drum, and divide by the power. 

To find the radius of the drum.— Multiply the power by 
the radius of the wheel, and divide by the weight. 

To find the weight.— Multiply the power by the radius 
of the wheel, and divide by the radius of the drum. 

Let W be the weight, D the radius of the drum, R the 
radius of the wheel and P the power required to lift the 
weight, then for a Wheel and Drum system: (Fig. 70.) 




Fig. 70. 



88 



MACHINE SHOP PRACTICE 



P= 



WXD 
R 



D= 



PXR 
W 



R= 



WXD 



W= 



PXR 
D 



For a Crank, Pinion and Gear and Drum system: 
71.) 



(Pig. 



PINION/' 




P= 



WXDXP 



W= 



RXG 
PXRXG 



-^^- DXP 

U--E-- ■* *D*I 

Fig. 71. 

To determine the amount of effective power produced 
from a given power by means of a crank, pinion and gear, 
and drum system.— Multiply the diameter of the circle de- 
scribed by the crank or turning handle by the number of 
revolutions of the pinion to one of the wheel. Divide the 
product by the diameter of the drum and the quotient is 
the ratio of the effective power to the exertive force. 
Pig. 71. 

Given any two parts of a crank, pinion and gear, and 
drum system, to find the third, that shall produce any re- 
quired proportion of mechanical effect.— Multiply the two 
given parts together, and divide the product by the re- 
quired proportion of effect, the quotient is the dimensions 
of the other part. 



D= 



PXRXG 
WXP 



R= 



WXDXP 



PXG 



p=Either pitch diameter or number of teeth in the pinion. 
G=Either pitch diameter or number of teeth in the gear. 



APPLIED MECHANICS 



89 



Let E be the ratio of the effective power to the effective 
force produced, then 

KXG 



E=3.1416 



DXP 



The Pulley or Sheave. 

The pulley or sheave is a wheel over which a rope is 
passed to transmit the force applied to the cord in an- 
other direction. There are two kinds of pulleys, the one 
turning on fixed centers, the other turning on traversing 
centers. 

The fixed or stationary pulley (Fig 72'). This acts like 
a lever of the first kind. It affords no mechanical advan- 
tage, and merely changes the direction of the force, and 
does not alter its intensity, but it affords great facilities in 
the application of force, as it is easier to pull downwards 
than upwards. In this class of pulley the power is equal 
to the weight to be raised. 



/////////////////////////////////////////A 





Fig. 72. Fig. 73. 

The movable pulley (Fig. 73).— This acts like a lever of 
the second kind. One end of the rope is suspended to a 



90 



MACHINE SHOP PRACTICE 



fixed point, as a fulcrum, in a beam, and the weight is at- 
tached to the axis of the pulley. This kind of pulley- 
doubles the power at the expense of the speed, and the 
product of the power by the diameter of the pulley, is 
equal to the product of the weight by the radius of the 
pulley. 

A movable pulley acting as a lever of the third kind is 
shown at Fig. 74. One end of the cord is fixed to a floor, 
and the weight is attached to the other end, the power 

being applied to the axis. The 
power is equal to twice the 
weight, and the product of the 
power by the radius of the 
pulley is equal to the product 
of the weight by the diameter 
of pulley. In the arrange- 
ment shown at Fig. 75 the 
power is equal to one-half the 
weight. 

A combination of movable 
pulleys with separate and par- 
allel cords is shown at Fig. 76. 
Each system reduces the re- 
sistance to the extent of one- 
half, hence the power may be 
found by dividing and sub- 
dividing the weight successive- 
ly by 2, as many times as 
there are moveable pulleys. 
The weight may be found by multiplying the power suc- 
cessively by 2, as many times as there are moveable pul- 
leys. 

To find the power.— Divide the weight to be raised by 
the number of cords leading to, from, or attached, to the 
power block. The quotient is the power required to pro- 
duce an equilibrium, provided friction did not exist. 




S///////////////////////M/ 



m77. 



Fig. 74. 



APPLIED MECHANICS 



91 



When the fixed end of the rope is attached to the fixed 
block, the power may be found by dividing the weight by 
twice the number of moveable pulleys. When the fixed 




Pig. 76. 



end of the rope is attached to the moveable block, the 
power may be found by dividing the weight by twice the 
number of moveable pulleys plus 1. 

To find the number of sheaves or pulleys required. Di- 
vide the power to be raised by the power to be applied; 
the quotient is the number of sheaves in, or cords attached 
to the rising block. 

To find the weight that will be balanced by a given 
power.— When the rope is attached to the fixed block, mul- 
tiply the power by twice the number of moveable pulleys. 

When the rope is attached to the moveable block multi- 
ply the power by twice the number of moveable pulleys 
plus 1. 



92 



MACHINE SHOP PRACTICE 
The Inclined Plane. 



The inclined plane (Fig. 77) is properly the second ele- 
mentary power, and may be defined the lifting of a load 
by regular instalments. In principle it consists of any 
right line not coinciding with, but laying in a sloping di- 
rection to, that of the horizon; the standard of compari- 
son of which commonly consists in referring the rise to 




so many parts in a certain length or distance, as 1 in 100, 
1 in 200, etc., the first number representing the perpen- 
dicular height, and the latter the horizontal length in at- 
taining such height, both numbers being of the same de- 
nomination, unless otherwise expressed. 

In using an inclined plane for the purpose of raising 
loads to a higher level, the power is applied parallel to 
the inclined plane, and the weight is raised in opposition 
to gravity, the work done on it is expressed by the prod- 
uct of the weight and the vertical height of the inclined 
plane. 

The advantage gained by the inclined plane, when the 
power acts in a parallel direction to the plane, is as the 
length to the height. 

To find the power.— Multiply the weight by the height 
of the plane, and divide by the slant length. The quotient 
is the power. 

To find the weight.— Multiply the power by the slant 
length of the plane, and divide by the height. 



APPLIED MECHANICS 



93 



To find the height of the inclined plane.— Multiply the 
power by the slant length, and divide by the weight. 

To find the slant length of the inclined plane.— Multiply 
the weight by the height of the plane, and divide by the 
power. 

Let W be the weight to be drawn up the inclined plane. 
H the height and S the slant length of the incline. If IE 
be the power required to draw the weight W up the in- 
clined plane, then 



WXH 

S 



w= 



PXS 
H 



H= 



PXS 

w 



s=va 2 +H 2 



The Wedge. 

The wedge is a double inclined plane, 
consequently its principles are the same. 
When two bodies are forced asunder by 
means of the wedge in a direction parallel to 
its head : Multiply the resisting power by 
half the thickness of the head or back of 
the wedge, and divide the product by the 
length of one of its slant sides. The quo- 
tient is the force required equal to the re- 
sistance. 



KhM 




Fig. 78. 



F=Force required. P=Resisting power. 

_ PXH ^ FX25 ,_. ^ ox 
F=— — F=—— (Fig. 78.) 



25 



S=Slant side of wedsre= 



v? 



H 2 -fL 2 



When only one of the bodies is moveable, the whole 
breadth of the wedge is taken for the multiplier, and the 
following rules are for such wedges, acting under pressure 
only on the head of the wedge, or at the point of the 
wedge by drawing. 



94 



MACHINE SHOP PRACTICE 



To find the transverse resistance to the wedge or weight. 

—Multiply the power by the length of the slant side of the 
wedge, and divide by the breadth of the head. 

To find the power.— Multiply the weight or transverse 
resistance by the breadth of the head and divide by the 
length of the slant side of the wedge. 

To find the length of the slant side of the wedge.— 
Multiply the weight by the breadth of the wedge and di- 
vide by the power. 

To find the breadth of the wedge.— Multiply the power 
by the length of the slant side of the wedge, and divide 
by the weight. 



F= Force required. 
W _PXH FXS 



P=Kesisting power. 
(Fig. 79.) 



S=Slant side of wedge=i/H 2 +L 2 

Note. — For all practical purposes the length L may be 
used instead of the slant length S of the side. 





The Screw. 



Fig. 80. 



The screw, Fig. 80, in principle, is that of an inclined 
plane wound around a cylinder which generates a spiral 



APPLIED MECHANICS 95 

of uniform inclination, each revolution producing a rise 
or traverse motion equal to the pitch of the screw, or dis- 
tance between two consecutive threads. The pitch being 
the height or angle of inclination, and the circumference 
the length of the plane when a lever is not applied. The 
lever being a necessary qualification of the screw, the cir- 
cle which it describes is taken, instead of the screw's cir- 
cumference, as the length of the plane, the mechanical ad- 
vantage is therefore as the circumference of the circle 
described by the lever where the power acts, is to the 
pitch of the screw, so is the force to the resistance. 

As the circumference of a circle is equal to the radius 
multiplied by twice 3.1416, or 6.2832, hence the following 
rules for the screw. 

To find the power.— Multiply the weight by the pitch of 
the screw and divide by the product of the radius of the 
handle by 6.2832. 

To find the weight.— Multiply the power by the product 
of the radius of the handle by 6.2832 and divide by the 
pitch of the screw. 

To find the pitch of the screw.— Multiply the power by 
the product of the radius of the handle by 6.2832 and di- 
vide by the weight. 

To find the length or radius of the handle.— Multiply the 
weight by the pitch of the screw and divide by the prod- 
uct of the power by 6.2832". 

P=Lifting power of jack. R=Length of lever. 
F=Force required at end of lever. 
N=Nuniber of threads per inch of jack screw. 



P=6.283(NXRXF) F= 



6.283 (NXR) 



P P 

N= R= 



6.283 (RXF) 6.283 (NXF) 



96 MACHINE SHOP PRACTICE 

The Safety Valve. 

Safety Valves. In order to find the weight to be placed 
on the end of a safety valve lever to balance a given 
pressure of steam on the valve, it is necessary to ascertain 
the load on the valve due to the weight of the lever. The 
leverage with which the weight of the lever acts is meas- 
ui ed by the distance of its center of gravity from the ful- 
crum. The center of gravity may be found by balancing 
the lever on a knife edge, and the weight of the lever and 
valve may be obtained by weighing them. 

In Fig. 81, W is the weight at the end of the lever, L is 
the distance between the weight and the fulcrum, G is the 
distance of center of gravity of the lever from the ful- 
crum, R is the distance between the center of the valve "V 
and the fulcrum. 



Fig. 81. 

To find the weight to be placed on the end of the level 
proceed as follows. Multiply the area of the valve V by 
the pressure in pounds per square inch above the atmos- 
phere, and call the product A. 

Multiply the weight of the lever by the distance of the 
center of gravity of the lever from the fulcrum, and di- 
vide by the distance between the center of the valve and 
the fulcrum, and add the weight of the valve to the quo- 
tient, and call the result B. 



APPLIED MECHANICS 97 

Subtract B from A, multiply the remainder by the dis- 
tance between the center of the valve and the fulcrum, 
and divide by the distance between the weight and the 
fulcrum, the quotient will be the weight to place on the 
valve. 

To find the pressure on the valve in pounds per square 
inch above the atmosphere. Multiply the weight of the 
lever by the distance of the center of gravity of the lever 
from the fulcrum, and call the product C. 

Multiply the distance between the weight and the ful- 
crum by the weight at the end of the lever, and call the 
product D, add C to D, divide by the distance between 
the center of the valve and the fulcrum, and add the 
weight of the valve to the quotient, then divide by the area 
of the valve V; the quotient will be the steam pressure 
in pounds per square inch, at which the valve will rise. 

To find the length of lever, or distance between the 
weight and the fulcrum. Multiply the pressure of the 
steam in pounds per square inch above the atmosphere by 
the area of the valve V, and call the product E. 

Multiply the weight of the lever by the distance of the 
center of gravity of the lever from the fulcrum, divide by 
the distance between the center of the valve and the ful- 
crum, and add the weight of the valve to the quotient, 
and call the result F. 

Subtract F from E, multiply the remainder by the dis- 
tance between the center of the valve V, and the fulcrum,, 
and divide by the weight at the end of the lever, the quo- 
tient will be the distance between the weight and the ful- 
crum. 

Counterbalanced safety-valve levers. If the lever be pro- 
longed beyond the fulcrum, and provided with a weight 
sufficient to balance the weight of the lever, valve, and con- 
nections, the rules become simplified, and are as follows: 

To find the weight to be placed on the lever. Multiply 



MACHINE SHOP PRACTICE 



the pressure in pounds per square inch above the atmos- 
phere by the area of the valve V, and by the distance be- 
tween the center of the valve and the fulcrum, and divide 
by the distance between the weight and the fulcrum. 

To find the length of lever or distance between the 1 
weight and the fulcrum. Multiply the pressure in pounds 
per square inch above the atmosphere by the area of the 
valve V, and by the distance between the 'center of the 
valve and the fulcrum, and divide by the weight at the 
end of the lever. 

To find the pressure on 
the valve in pounds per 
square inch above the 
atmosphere. Multiply the 
weight at the end of the 
lever by the distance be- 
tween the weight and the 
fulcrum, and divide by 
the product of the area 
of the valve V by the dis- 
tance between the center 
of the valve and the ful- 
crum. 

Safety-valve with spring 
balance. When the valve 
V is held down by a spring, 
the lever is generally dis- 
pensed with as shown in 
Fig. 82. 




Fig. 82. 



Gravity and the Velocity of Falling Bodies. 
Gravity is the action of universal attraction which draws 
all bodies towards each other, and by which bodies on the 
surface of the earth are drawn towards its centre. The 
line which a falling body describes, or the direction of 
gravity, is called the vertical line, the curvature of the 



APPLIED MECHANICS 99 

earth being quite unappreeiable for small distances. Grav- 
ity is considered to act in parallel lines, and its direction 
is indicated by the plumb-line. 

The center of gravity is that point in a body or system 
of bodies on which, if rested or suspended, the whole will 
remain in a state of rest. Thus, if a wall or other struc- 
ture be raised perpendicular to the base, it will remain 
secure whilst in that state, but if the foundation be not 
sufficiently solid and allow it to depart so far from the 
vertical position that the center of gravity overhangs the 
edge of the base, the structure must fall unless the parts 
anchored anchored together. 

The center of gravity of a cylinder, prism, or any other 
body, the parallel sections of which are equal, is in the 
middle of the axis of that body. 

In a cone or any other pyramid, the distance of the cen- 
ter of gravity from the base is one-fourth of the axis. 

In a hemisphere the distance of the center of gravity is 
three-eighths of the radius from the center. 

Force of gravity or gravitation is an accelerated velocity 
which heavy bodies acquire, in falling freely from a state 
of rest. Thus the velocity that a body will acquire in one 
second of time equals 32.2 feet, the distance fallen being 
16.1 feet; and if the times or seconds be in an arithmeti- 
cal ratio, as 1, 2, 3, 4, etc., the spaces fallen through will 
be successively as the numbers 1, 3, 5, 7, etc., and the to- 
tal space passed through as the geometrical progression, 
1, 4, 9, 16, etc. The velocity is 32.2 feet multiplied by the 
number of seconds in falling from rest, and the square of 
the velocity is equal to twice 32.2 times the space fallen 
through. The space fallen through is equal to 16.1 multi- 
plied by the square of the number of seconds. 

Weight is the force apparent when gravity acts upon 
mass. Mass is matter without reference to weight. When 
mass or matter is prevented from moving under the stress 
of gravity, its weight can be appreciated. 



100 MACHINE SHOP PRACTICE 

v=Velocity in feet per second. 
t=Time in seconds 
h=Height in feet 
g=gravity constant=32.2 






-v 



2 g \ g 

Weight does not enter into consideration in the above 
formulas. In a perfect vacuum a feather should fall from 
a given height in the same time that a pound weight 
would. 

To find the final velocity in feet per second. Multiply 
the time in seconds by 32.2. 

To find the height of the fall in feet. Multiply the 
square of the time in seconds by 16.1. 

To find the time of falling in seconds. Divide the height 
in feet by 16.1 and extract the square root of the quotient. 

Example: Find the velocity that a body will acquire in 
five seconds: 32.2X5=161 feet. 

Example: Find the space fallen through in seven sec- 
onds: 16.1X7 2 =788.9 feet. 

Example: Find the velocity that a body will acquire in 
falling through 120 feet: V1 20 X 6 ^4==V 7728 ==87.9 feet. 

The velocity acquired by a body falling through a given 
height is the same, whether it fall freely or descend upon 
a plane any way inclined. 

Force of gravity is the cause of retarded and of accel- 
erated motion on inclined planes, the acting force being 
as the height of the plane to its length. Eight pounds 
traction will overcome 2,000 pounds, or one ton of weight, 
but on an incline or rise of 1 in 350, the amount of trac- 
tion to overcome the same weight must be Wo-— 6.4+8 
=14.4 pounds. Again, if the weight be descending, then 
the force of traction is diminished in an equal ratio, and 



APPLIED MECHANICS 



101 



Table No. 5— Velocity of Falling Bodies: Table of 




Accelerated Motion. 




Time in 

seconds the 

body is 

falling. 


Space in feet that a 

falling body passes 

through during 

each second. 


Space in feet 
through which a 
body will fall in 

a given time. 


Velocity in feet per 
second that a fall- 
ing body will ac- 
quire during the 
time given. 


1 


16.1 


16.1 


32.2 


2 


48.3 


64.4 


64.4 


3 


80.5 


144.9 


96.6 


4 


112.7 


257.6 


128.8 


5 


144.9 


402.5 


161.0 


6 


177.1 


579.6 


193.2 


7 


209.3 


788.9 


225.4 


8 


241.5 


1030.4 


257.6 


9 


273.7 


1304.1 


289.8 


10 


305.9 


1610.0 


322.0 



the weight accelerated by gravity, thus 8—6.4=1.6 pounds, 
the force of traction on the descending plane. 

Force of gravity is also the restrictive cause to a pendu- 
lum's motion. Consequently its motion at any place is 
dependent upon the energy of the force of gravity at that 
place. 

Pendulums of the same length vibrate slower, the nearer 
they are brought to the equator, on account of the earth's 
spheroidal form, its polar axis being about twentj'-six miles 
shorter than its equatorial diameter, for which reason grav- 
ity is lessened l-289th part, the centrifugal force arising 
from the diurnal motion of the earth being greater at the 
equator than at the poles. 

The measure of the force of gravity in feet per second 
at any place, is equal to the length of a pendulum in feet, 
divided by the square of the time in seconds between each 
of its oscillations, and the quotient multiplied by 9.8696, 
the product equals the number of feet by which gravity 



102 MACHINE SHOP PRACTICE 

will at that place increase the velocity of the descent of a 
falling body in each second of time. 

The space through which a body will fall during the 
time of one vibration of a pendulum vibrating seconds, is 
to half the pendulum's length as the square of the circum- 
ference of a circle is to the square of its diameter. 
The length of a Pendulum to vibrate Seconds, or Sixty 
Times in a Minute. 

At the Equator, equals 39.0152 inches. 

In the latitude of London 39.1393 inches. 

In the latitude of Edinburgh 39.1555 inches. 

In the latitude of Paris 39.1286 inches. 

In the latitude of New York 39.1011 inches. 

In the latitude of Madras 39.0263 inches. 

In the latitude of Greenland 39.2033 inches. 

SPECIFIC GRAVITY, CENTER OF OSCILLATION, 
CENTRIFUGAL FORCE, ETC. 

Specific Gravity. The comparative density of various 
substances is expressed by the term specific gravity, which 
affords the means of readily determining the bulk from the 
known weight, or the weight from the known bulk. This 
is found especially useful in cases where the substance is 
too large to admit of being weighed, or too irregular in 
shape to allow of correct measurement. The standard with 
which all solids and liquids are thus compared, is that of 
distilled water, one cubic foot of which weighs 1000 ounces 
avoirdupois. The specific gravity of a solid body is deter- 
mined by the difference between its weight in the air and 
in water. Thus: If the body be heavier than water, it 
will displace a quantity equal to its own bulk, and will 
lose as much weight on immersion as that of an equal bulk 
of the water. If the body be weighed first in the air, and 
then in the water, and its weight in the air be divided by 
the difference between the two weights, and the quotient 
will be its specific gravity, that of water being unity. 

If the body be lighter than water, it will float, and dis- 



APPLIED MECHANICS 



103 



place a quantity of the water equal to it in weight, the 
bulk of which will be equal to that only of the part im- 
tnersed. A heavier substance must therefore be attached 
to it, so that the two may sink in the fluid. Then the 
weight of the lighter substance in the air must be added 
to that of the heavier substance in water, and the weight 
of both united in water be subtracted from the sum; the 
weight of the lighter body in the air must then be divided 
by the difference, and the quotient will be the specific grav- 
ity of the lighter substance required. 

The specific gravity of a fluid may be determined by 
taking a solid body, heavy enough to sink in the fluid, and 
of known specific gravity, and weighing it both in the air 
and in the fluid. The difference between the two weights 
must be multiplied by the specific gravity of the solid 
body, and the product divided by the weight of the solid 
in the air, the quotient will be the specific gravity of the 
fluid, that of water being unity. 



Table No. 6. — Specific Gravity and Weight per Cubic 




Foot of Metals. 






Spe- 


Wt.in 




Spe- 


Wt.in 




cific 


Lbs. 




cific 


Lbs. 


Metal 


Grav- 


per 


Metal 


Grav- 


per 


■ 


ity. 


Cu.ft. 
162 




ity. 


Cu.ft. 
535 


Aluminum 


2592 


Gun Metal 


8560 


Antimony 


6704 


418 


Iron — Cast 


7200 


450 


Bismuth 


9808 


613 


" — Ma'lble 


7360 


460 


Brass — Cast 


8064 


504 


" —Wrought 


7680 


480 


" —Sheet 


8160 


510 


Lead 


11360 


710 


Bronze — Aluminum 


8000 


500 


Nickel 


8272 


517 


" — Phosphor 


8480 


530 


Platinum 


20976 1313 


Cadmium 


8608 


538 


Silver (pure) 


10480 


655 


Copper — Cast 
" —Sheet 


8672 


542 


Steel — Cast 


7776 


486 


8768 


548 


" —Mild 


7840 


490 


" —Wire 


8768 


548 


Tin, Cast. 


7296 


456 


Gold (pure) 


19254 


1204 


Zinc, Cast. 


7008 


438 



104 



MACHINE SHOP PRACTICE 



Table No. 7. — Specific Gravity and Weight per Cubic 




Foot of Substances, 






Spe- 


Wt.in 




Spe- 


Wt.in 


Substance 


cific 
Grav- 


Lbs. 
per 


Substance 


cific 
Grav- 


Lbs. 
per 




ity. 


Cu.ft. 




ity. 


Cu.ft. 


Ash, White 


608 


38 


Mahogany 


848 


53 


Asphaltum 


1392 


87 


Maple 


784 


49 


Brick — Pressed 


2400 


150 


Marble 


2688 


168 


" — Common 


2000 


125 


Mica 


2928 


183 


Cement — Portland 


1440 


90 


Oak, White 


800 


50 


" — Louisville 


800 


50 


Pine— White 


400 


25 


Cherry- 


672 


42 


— Northern 


544 


34 


Chestnut 


656 


41 


— Southern 


720 


45 


Clay — Common 


1920 


120 


Quartz 


2640 


165 


— Potters 


1760 


110 


Rosin 


1104 


69 


Coal — Anthracite 


1488 


93 


Salt 


720 


45 


" — Bituminous 


1344 


84 


Sand — Dry 


1568 


98 


Coke 


416 


26 


" —Wet 


2240 


140 


Earth 


1520 


95 


Sandstone 


2416 


151 


Ebony 


1216 


76 


Shale 


2592 


162 


Elm 


560 


35 


Slate 


2800 


175 


Flint 


2592 


162 


Spruce 


400 


25 


Glass, plate 


2448 


153 


Sulphur 


2000 


125 


Granite 


2656 


166 


Sycamore 


592 


37 | 


Gravel 


1920 


120 


Peat 


416 


26 


Hemlock 


400 


25 


Teak 


752 


47 i 


Hickory 


848 


53 


Walnut, Black 


608 


38 


Ice 


960 


60 


Wax, Bees 


960 


60 


Ivory 


1824 


114 


Willow 


576 


36 


Lignum Vitse 


1328 


83 


Yew — Spanish 


800 


50 


Magnesium 


1744 


109 


" —Dutch 


768 


48 





APPLIED MECHANICS 



105 



Table No. 8— Specific Gravity and Weight per Cubic 


Foot of Liquids. 


Liquid. 


Specific Gravity. 


Weight in Lbs. 
per Cubic Foot. 


Alcohol — Commercial 




51| 


" — Absolute 


797 


49.8 


Acid — Muratic 


1200 


75 


" —Nitric 


1216 


76 


" — Sulphuric 


1856 


116 


Ether— Nitric 


908 


63 


" — Muratic 


730 


45.6 


Oil — Linseed 


941 


58.8 


" —Olive 


914 


57.1 


" —Whale 


923 


57.7 


Petroleum — Crude 


880 


55 


Spirit — Proof 


922 


57.5 


" —of Wine 


830 


51.9 


Tar— Gas 


1008 


62 


" —Wood 


992 


63 


Turpentine 


864 


54 


Water— Distilled 


997 


m 


" —Sea 


1024 


64 



The Centre of Oscillation is a certain point in a vibrating 
body into which all its force is collected, and at which, if 
an obstacle be applied, motion will instantly cease. The 
most simple means by which to ascertain the centre of 
oscillation in a compound pendulum, is to suspend a small 
ball by a fine thread in front of that in which the centre 
of oscillation is required, then to lengthen or shorten the 
thread until the vibrations of each are alike, then stop both 
and let them hang freely. Opposite the centre of the ball 
is the centre of oscillation. 

Specific Gravity of Bodies. 

As one cubic foot of fresh water at 62 degrees Fahren- 
heit, weighs 1000 ounces avoirdupois, it (1000) is therefore 
adopted as the standard of comparison to which the densi- 
ties of other bodies are referred. 



106 



MACHINE SHOP PRACTICE 



Table No. 9 — Comparative Weights of Different 
Metals, etc. 



Cast Iron=1. 

Wrought Iron . . 1.049 

Steel 1.080 

Brass ..... 1.160 

Copper 1.219 

Gun Metal . . . 1.209 

Lead 1.560 

Wrought Iron=1. 
Cast Iron ... .95 

Steel 1.026 

Brass 1.097 

Gun Metal . .. 1.150 

Copper . . . . 1.152 

Lead 1.500 

Steel=1. 
Cast Iron . . . .929 
^ Wrought Iron . . .974 

Brass 1.071 

Gun Metal . . . 1.121 

Copper .... 1.124 

Lead 1.454 

Brass=1. 
Cast Iron . . 
Wrought Iron 
Steel .... 
Gun Metal 



.865 
. .915 
.934 
. 1.045 
Copper .... 1.051 
Lead 1.355 



Gun Metal=1. 
Cast Iron . . . .829 
Wrought Iron . . .879 

Steel 898 

Brass 958 

Copper .... 1.001 
Lead 1.296 

Copper=1. 
Cast Iron . . 
Wrought Iron 
Steel .... 
Brass „ . . 
Gun Metal . . 
Lead . . . 



.831 
.868 
.888 
.949 
.998 
1.298 



White Metal=1. 
Cast Iron . . . .793 
Wrought Iron . . .814 

Steel 846 

Gun Metal . . . .912 
Copper .... .954 
Lead 1.201 

Lead=1. 
Cast Iron . . . .641 
Wrought Iron . . .670 

Steel 689 

Brass 739 

Gun Metal ... .771 
Copper ..... .778 



Yellow Pine=1. 
Cast Iron 16.00 I Brass . . 18.80 | Copper . 19.30 
Steel . . 17.00 I Gun Metal 19.00 | Lead . . 24.00 



Example: A Wrought-Iron plate weighs 700 pounds, 
required the weight of a similar plate of Gun Metal. 
Answer: 700 X 1.15 = 805 pounds. 



APPLIED MECHANICS 107 

Centrifugal force signifies the tendency that bodies ac- 
quire, by velocity of circular motion, to fly off in a tangen- 
tial line from the centre of revolution, the amount of ten* 
dency being as the square of the velocity of the body in 
motion. Multiply the square of the number of revolu- 
tions per minute by the radius of the circle in feet, by 
the weight of the body, and by .000331. The product is 
the centrifugal force in terms of the body's weight. 

Centripetal force is that force by which a body would 
tend to the centre of motion, if not urged from it by cen- 
trifugal force. The balls of the governor of a steam- 
engine conspicuously indicate this force when the velocity 
of the engine is becoming reduced by over resisting force, 
or by a scant supply of steam. 

The Centre of gyration, in a revolving body, is a cer- 
tain point into which the whole momentum of the mass is 
concentrated, and from which point the greatest amount of 
effective energy is transmitted. Any point in the circum- 
ference of a circle, whose radius is the distance of the 
centre of rotation from the centre of gyration, is equally 
entitled to be called a centre of gyration. The radius of 
this circle is the radius of gyration. 

To find the distance of the centre of gyration from the 
centre of revolution. Multiply the amount of acting force, 
the distance at which it is applied from the centre of revo- 
lution, by the time of revolution observed in seconds, and 
by 32.2 and divide the product by the weight multiplied by 
its velocity, and the quotient is the distance from the 
centre of motion to the centre of gyration. 

Momentum, or quantity of motion, signifies the product 
of the moving weight multiplied by the velocity, and is 
usually estimated in pounds, moving at the given velocity 
in feet per second. A body weighing 10 pounds and mov- 
ing at the rate of 10 feet per second, has a momentum of 
100. 



108 MACHINE SHOP PRACTICE 

Percussion. The quantity of work stored in a moving 
body is the same as that which would be accumulated in 
it by gravity, if it fell from a height sufficient to give it 
the same velocity. The effect of percussive machines is 
produced by expending the work accumulated in the strik- 
ing body. 

Pile driving. In a pile-driving machine, with a ram 
weighing 336 pounds and 10 feet fall, the work accumu- 
lated in the monkey in each fall, will be 336 pounds X 10 
feet=3360 foot-lbs. If this work be expended in driving 
the pile 1 inch into the ground the force exerted will be 
3360 foot-pounds X 12 inches=40320 pounds. 

To find the work accumulated in a moving body in foofc 
pounds, Multiply the weight in pounds by the square of 
the velocity in feet per second, and divide by 64.4. 

Level properly signifies points equidistant from the cen- 
tre of the earth on its surface. Any level taken by an instru- 
ment is only a tangent line to the earth's curvature, and is' 
generally termed the apparent level. The earth is nearly 
a sphere, with a mean diameter of 7925 miles, and if the 
square of the distance between any two points on its sur- 
face be divided by its diameter, the quotient will equal 
the excess of altitude between the summit of the vertical 
diameter and that of the other point. At one mile distance 
the excess by level with an instrument becomes 7.962 
inches, at two miles it is 31.848, being as the square of the 
distance. The excess subtracted from the apparent level, 
equals true level as required for extensive levelling opera- 
tions. 

Capillary attraction is a property observable in small 
tubes, flat, thin spaces, porous substances, as sponge, wick, 
worsted, threads, etc., of raising water or other fluids above 
the natural level. The principle is used for obtaining a 
continuous supply of lubricating fluid _ between surfaces in 
motion by a syphon of threads; one end of which is im- 



APPLIED MECHANICS 109 

mersed in oil, the other being inserted in and supported 
by the tube through which the fluid is conducted. 

FRICTION. 

Friction is an effect produced by bodies rubbing one 
upon another, which acts as a retarding influence in the 
motion of all mechanical devices, but might be considerably 
diminished by a due regard to its laws, and a proper at- 
tention to the selection of materials on which a smooth 
surface may be attained, and which are least liable to 
wear or become hot, and cause a roughness to arise when 
in working contact. 

The ordinary theory of friction may be briefly stated to 
be as follows: When no lubricant is interposed, the fric- 
tion of any two surfaces is directly proportional to the 
force with which they are pressed perpendicularly together, 
so that for any two given surfaces of contact, there is a 
constant ratio of the friction to the perpendicular pres- 
sure. That is, a double pressure will produce a double 
amount of friction, or a triple pressure a triple amount. 

When no lubricant is interposed, the amount of the fric- 
tion is in every case wholly independent of the extent of 
the surfaces in contact, so that the force with which two 
surfaces are pressed together being the same, their fric- 
tion is the same, whatever may be the extent of their sur- 
faces of contact. 

When lubricants are interposed, the amount of friction 
depends more upon the nature of the lubricant than upon 
that of the surfaces of contact, and the nature of the 
lubricant to be applied must be governed by the pressure 
or weight. The consistency of a lubricant should be such 
as just prevent the bodies coming into contact with each 
other. 

The friction of metals, without a stratum of lubricant 
interposed, varies as their ■ hardness, the harder metals 
producing less friction than the softer ones. 



110 MACHINE SHOP PRACTICE 

Without lubricants, and within the limits of 32 pounds 
pressure per square inch, the friction of hard metal upon 
hard metal may be estimated at about one-sixth of the 
whole pressure. 

The sliding friction of plane surfaces in contact is in- 
creased by heat, and is diminished by polishing and efficient 
lubrication; and it is less in motion than at starting. That 
portion of the pressure required to overcome friction is 
called the coefficient of friction. For oak and other woods, 
and cast-iron and other metals, each sliding on each other, 
and lubricated, the coefficient varies according to the ef- 
ficiency of the lubrication, from .07 to .04 for sliding fric- 
tion. Rolling friction is considerably less than sliding 
friction. 

The friction of motion was formerly considered to be 
wholly independent of the velocity of the motion. The re- 
sults of recent experiments show that the resistance of 
friction increases with the velocity, and that the coefficient 
of friction is extremely low, amounting in some cases to 
only .001, or a mere fraction of what it was formerly con- 
sidered to be. 

The experiments also show that the friction of lubricated 
bearings varies considerably with temperature. 

Belt Pulleys. 

Where motion has to be communicated from one shaft- 
to another by means of a belt passing over pulleys, to find 
the diameter of either pulley, to suit that of another with 
increased or diminished velocity, so that the same length of 
belt may be suitable without alteration, the question un- 
avoidably divides itself into two, as the pulley whose diam- 
eter is required is less or greater than that of a pulley 
which is known. When this point is uncertain, multiply 
the radius of the known pulley by 3.1416, and increase the 
product by the distance between the centres of the shafts 



APPLIED MECHANICS 111 

in inches. If this sum which may be called the trial num- 
ber, is greater than half the length of the belt, the re- 
quired pulley is less than the given one, but if less, 
then the required pulley is the greater. In both of these 
cases, divide the difference between the trial number and 
half the length of the belt, by the distance between the 
centres of the shafts. 

When the required pulley is less than the given one. Take 
double the number from 2.4674, and subtract the square 
root of the remainder from 1.5708, and call the difference 
A. Multiply the number A by the distance between the 
centres of the shafts, and the remainder, taken from the 
radius of the large pulley, will give the radius of the less 
one. 

When the required pulley is greater than the given one. 
Add double the number to 2.4674, and from the square root 
of the sum subtract 1.5708, and caH the remainder B. 
Multiply the number B by the distance between the cen- 
tres of the shafts and the product, added to the radius of 
the given or less pulley, will give the radius of the re- 
quired, or greater pulley. 

Gear Wheels. 

Motion is in many cases transmitted by means of gear 
wheels, and accordingly as the driving and driven are of 
equal or unequal diameters, so are equal or unequal veloci- 
ties produced. 

When time is not taken into account. Divide the greater 
Vjieter, or number of teeth, by the lesser diameter, or 
number of teeth, and the quotient is the number of revo- 
lutions the lesser will make for 1 of the greater. 

Example: How many revolutions will a pinion of 2k 
teeth make for 1 of a gear with 125 teeth 1 ? 

Answer: 125-^20=6.25, or 6*4 revolutions. 

Intermediate gears of any diameter, used-, to conneci 



112 MACHINE SHOP PRACTICE 

other gears at any required distance apart, cause no varia- 
tion of velocity more than otherwise would result if the 
first and last gears were in mesh. 

To find the number of revolutions of the last, to 1 of the 
first, in a train of gears and pinions. Divide the product 
of all the teeth in the driving by the product of all the 
teeth in the driven gears, and the quotient will equal the 
ratio of velocity required. 

Example: A gear of 42 teeth giving motion to one of 
12 teeth, on which shaft is a pulley of 21 inches diameter, 
driving one of 6 inches diameter, required the number of 
revolutions of the last pulley to one of the first gear. 

Answer: (42'X21)-M 12X6) =12.25, or 121/4 revolutions. 

Where increase or decrease of velocity is required to be 
communicated by gears, it has been demonstrated that the 
number of teeth on the pinion should not be less than 1 
to 6 of its wheel, unless there be other reasons for a 
higher ratio. 

When time must be regarded. Multiply the diameter, or 
number of teeth in the driving gear, by its velocity in any 
given time, and divide the product by the required velocity 
of the driven gear, the quotient equals the number of teeth, 
or diameter of the driven gear, to produce the velocity re- 
quired. 

Example: If a gear containing 84 teeth makes 20 revo- 
lutions per minute, how many teeth must another contain 
to work in contact, and make 60 revolutions in the same 
time? 

Answer: (84X20) -^60=28 teeth. 

The distance between the centres and velocities of two 
gears being given, to find their proper diameters. Divide 
the greatest velocity by the least. The quotient is the 
ratio of diameter the wheels must bear to each other. 
Hence, divide the distance between the centres by the 
ratio plus 1. The quotient will equal the radius of the 



APPLIED MECHANICS 113 

smaller gear, and subtract the radius thus obtained from 
the distance between the centres, the remainder will equal 
the radius of the other gear. 

Example: The distance of two shafts from centre to 
centre is 50 inches, and the velocity of one shaft is 25 
revolutions per minute, the other shaft is to make 80 
revolutions in the same time. Required the proper diam- 
eters of the gears at the pitch lines. 

Answer: 8-^25=3.2, the ratio of velocity, and 50-^- 
(3.2-f-l)=11.9, the radius of the smaller wheel; then 
50— (11.9X38.1) the radius of the larger gear. Their 
diameters are therefore 11.9X2=23.8, and 38.1X2=76.2 
inches. 

To obtain or diminish an accumulated velocity by means 
of gears and pinions, or gears, pinions, and pulleys, it is 
necessary that a proportional ratio of velocity should exist, 
and which is obtained thus: Multiply the given and re- 
quired velocities together, and the square root of the 
product is the mean or proportionate velocity. 

Example: Let the given \°.locity of a gear containing 
54 teeth equal 16 revolutions per minute, and the given 
diameter of an intermediate pulley equal 25 inches, to ob- 
tain a velocity of 81 revolution^ in a machine. Required 
the number of teeth in the intermediate gear, and the 
diameter of the last pulley. 

Answer: V 8 1X1 6 = 36 tlle mean velocity, (54X16)-t-36= 
24 teeth, and (25X36) -7-81=11.1 inches, the diameter of 
the pulley. 

Diametral Pitch System of Gears. 

The Diametral pitch system is based on the number of 
teeth to one inch diameter of the pitch circle. Formulas 
are herewith given so that if the number of teeth in the 



114 MACHINE SHOP PRACTICE, 

gear and the diametral pitch are known, the pitch diameter 
of the gear may be found, also the outside diameter, the 
working depth and clearance at the bottom of the tooth. 
Let P be the pitch diameter in inches, D the diametral 
pitch of the gear, C the circular pitch in inches, O the 
outside diameter in inches, T the thickness of the tooth 
at the pitch line in inches, W the working depth of the 
tooth in inches, and N the number of teeth in the gear, 
then 



P=Pitch diameter 




(1.) 


=Outside diameter 


-*£ 


(2.) 


D =Diametral pitch 


~P 


(3.) 


C =Circular pitch 


_3.142 
D 


(4.) 



2 
W=Working depth of tooth=-— =2-^D (5.) 

N =Number of teeth = PXD (6. ) 

T=Thickness of tooth = 1.571-^D (7.) 

Clearance at bottom of tooth= (8.) 

Example: Required, the pitch diameter of a gear with 
20 teeth and 4 diametral pitch. 

Answer: From Formula 1, as the pitch diameter is 
equal to the number of teeth divided by the diametral 
pitch, then 20 divided by 4 equals 5, as the required pitch 
diameter in inches. 



APPLIED MECHANICS 115 

Example: What is the outside diameter of the same 
gear ? 

Answer: From Formula % as the pitch diameter is 5 
inches and the diametral pitch 4, then 4 plus 2-4 equals 
4^ as the proper outside diameter for the gear. 

Example: What should be the diametral pitch of a gear 
with 30 teeth and 6 inches pitch diameter? 

Answer: From Formula 3, 30 divided by 6 squals 5, as 
the diametral pitch to be used for the gear. 

Example: Required the circular pitch of the teeth of a 
gear whose diametral pitch is 6. 

Answer: From Formula 4, 3.142 divided by 6 gives 
0.524 inches as the circular pitch of the teeth of the gear. 

Example: What should be the working depth of a tooth 
of 4 diametral pitch? 

Answer: From Formula 5, 2 divided by 4 gives 0.5 or 
one-half an inch as the working depth of the tooth. 

Example: How many teeth are there in a gear of 7 
inches pitch diameter and 7 diametral pitch? 

Answer: From Formula 6 the number of teeth is equal 
to 7 multiplied by 7, or 49 teeth in the gear. 

Example: What is the thickness at the pitch line of a 
tooth of 8 diametral pitch? 

Answer: By Formula 7 the thickness of the tooth at the 
pitch line is 1.571 divided by the diametral pitch, then 
1.571-^8 gives 0.196 inches as the thickness of the tooth. 

Example: What should be the correct clearance at the 
bottom of a tooth of 3 diametral pitch? 

Answer: From Formula 8 the clearance at the bottom 
of the tooth is equal to 0.157 divided by 3, which gives 
0.052 as the required clearance. 

Table No. 10 gives the dimensions of Involute Tooth Spur 
Gears from 1 to 16 Diametral pitch. 



116 



MACHINE SHOP PRACTICE 



Table No. 10 — Dimensions of Involute Tooth Spur 
Gears. 



Diametral 
Pitch. 


* Circular 
Pitch. 


Width of 
Tooth on 
Pitch Line. 


Working 

Depth of 

Tooth. 


Actual 

Depth of 

Tooth. 


Clearance 
at Bottom 
of Tooth. 


1 


3.142 


1.571 


2.000 


2.157 


0.157 


2 


1.571 


0.785 


1.000 


1.078 


0.078 


3 


1.047 


0.524 


0.667 


0.719 


0.052 


4 


0.785 


0.393 


0.500 


0.539 


0.039 


5 


0.628 


0.314 


0.400 


0.431 


0.031 


6 


0.524 


0.262 


0.333 


0.360 


0.026 


7 


0.447 


0.224 


0.286 


0.308 


0.022 


8 


0.393 


0.196 


0.250 


0.270 


0.019 


10 


0.314 


0.157 


0.200 


0.216 


0.016 


12 


0.262 


0.131 


0.167 


0.180 


0.013 


14 


0.224 


0.112 


0.143 


0.154 


0.011 


16 


0.196 


0.098 


0.125 


0.135 


0.009 



*The circular pitch corresponding to any diametral pitch number, may- 
be found by dividing the constant 3.1416 by the diametral pitch. 

Example: What is the circular pitch in inches corresponding to 4 dia- 
metral pitch? 

Answer: Dividing 3.1416 by 4 gives 0.7854 inches as the required cir- 
cular pitch. 



PROPERTIES OF STEAM 



Steam contains heat which is sensible to the thermometer, 
and also a quantity of heat of which the thermometer af- 
fords no indication, which is therefore called latent heat, 
hence, the vapor rising from water contains more heat than 
the water. In proof of the existence of latent heat, if one 
part by weight of steam at 212 degrees, be mixed with 
nine parts of water at 62 degrees, the result is water at 
178.6 degrees, therefore, each of the nine parts of water 
has received from the steam 116.6 degrees of heat, and con- 
sequently the steam has diffused or given out 116.6X9= 
1049.4 — 33.4=1016 degrees of heat which it must have con- 
tained. Again, if one gallon of water be transformed into 
steam at 212 degrees, and if that steam be mixed with 
water at 52 degrees, the whole will be raised to the boiling 
point, or 212 degrees. From experiments, it is ascertained 
that the latent heat in steam varies from 940 degrees to 
1044 degrees, the ratio of accumulation advancing from 212 
degrees, as the steam becomes more dense and of greater 
elastic force. 

The latent heat in steam makes it useful for beating, 
boiling and drying purposes. In the heating of buildings, 
it is applied with economy, efficiency, and simplicitj\ The 
steam becomes condensed during its circulation round the 
building, through the pipes of the heating apparatus, the 
latent heat being thus given to the pipes and diffused by 
radiation. In boiling, its efficiency is considerably in- 
creased, if advantage be taken of sufficiently enclosing the 
fluid and reducing the pressure on its surface by means 
of an air-pump; thus, water in a vacuum boils at about a 

119 



120 MACHINE SHOP PRACTICE 

temperature of 98 degrees, and in sugar-refining, where such 
means are employed, the syrup is boiled at 150 degrees. 

To calculate the amount of advantage gained by using 
steam expansively in a steam engine. 

When steam of a uniform force throughout the whole 
"length of stroke of the piston is used, the amount of 
effect produced is as the quantity of steam expended. But 
let the steam be shut off at any portion of the stroke, say 
at one half, it expands by degrees until the termination of 
the stroke, and then exerts half its original force. 

Divide the length of the stroke by the distance or space 
into which the boiler steam is admitted, and find the 
natural logarithm of the quotient, to which add 1, and the 
sum is the ratio of the gain. 

Example: An engine with a stroke of 6 feet has the 
steam cut off when the piston has moved through 2 feet. 
Required the ratio of gain by uniform and expansive force. 

Answr: 6-f-2=3. From Table No. 11 the natural logarithm 
of 3=1.098, and 1.098+1=21098 ratio of effect, that is, 
supposing the whole effect of the steam to be 3, the effect 
by the steam being cut off at one-third of the stroke=2.098. 

Let the greatest force of steam in the cylinder of an 
engine equal 48 pounds per square inch, and let it be cut 
off when the piston has moved 4^ inches, the whole stroke 
being 18. Required the equivalent force of the steam 
throughout the whole stroke. 

Answer: 18-^-4.5=4, and 48-^-4=12. Nat. Log. of 4^= 
1.386, and 1.386+1=2.386. Then 2.386X12=28.63 pounds 
per square inch. 

From Table No. 11 it may be plainly seen that, if the 
steam is cut off at one-third of the stroke, and expanded 
to the end of the stroke the work done is about twice that 
done by the steam during admission. 



PROPERTIES OF STEAM 



121 



Table No. 11 — Work Done by Steam During 
Admission and Expansion. 



Point of Cut Off. 



Cut Off at | 

Cut off at \ 
Cut off at i 
Cut off at i 
Cut off at 1 
Cut off at 1 
Cut off at 1 
Cutoff at iV 



stroke 
stroke 
stroke 
stroke 
stroke 
stroke 
stroke 
stroke 



Ratio of 

Expansion 

=R 



2 
3 
4 
5 
8 
9 
10 



Work done 

during 
Admission. 



Work done 
during expan- Total work 
sion=nat. done, 

log. R. 



0.262 

0.693 
1.098 
1.386 
1.609 
2.079 
2.197 
2.302 



1.262 
1.693 
2.098 
2.386 
2.609 
3.079 
3.197 
3.302 



The exact proportion is 1 :2.098 

If the steam had been admitted at its initial pressure 
throughout the whole stroke, three times the weight of 
steam would have been used, and the proportion of the 
work done in the two eases, supplying steam through the 
whole length of the stroke, or cutting off at one- third and 
expanding, would be as 3 to 2.09S, in other words, to get 
half as much more work out of the engine, three times the 
weight of steam, and therefore also weight of fuel, will 
be consumed in the first case as compared with the second. 

Condensation of steam is generally effected by cold 
water, the quantity of which may be estimated by the fol- 
lowing rule. From 1000 plus the temperature of the steam, 
subtract the required temperature of the condensed water, 
divide the remainder by the temperature of the condensed 
water minus the temperature of the cold or condensing 
water, and the quotient will equal the number of times that 
the quantity, for condensation, must exceed that by which 
the steam is formed. 

Example: Required the ratio or quantity of water for 



122 MACHINE SHOP PRACTICE 

condensation to 1 of water for the formation of steam, 
the temperature of the steam being 220 degrees and the 
required temperature of condensed water 18 degrees. 

(1000+220)- 180 . 

Answer: — ■ — — — — =8 times the quantity. 

180 — 52 

Pressure and Expansion of Steam. 

The pressure of steam is equal in all directions, and it 
is usual to measure the pressure with reference to that of 
the atmosphere, which is equal to 14.7 pounds per square 
inch of surface, and is the measure of one atmosphere of 
pressure. Vapors, of which steam is one, do not follow the 
law of permanent gases, according to which the volume 
of a given weight is inversely as the pressure. It has been 
demonstrated, on the contrary, that there exists a constant 
relation between the pressure, the density, and the tem- 
perature of steam, such that the pressure cannot be raised 
above a given maximum, without, at the same time, a cer- 
tain elevation of temperature. 

Volume and Pressure of Steam. If the volume be forci- 
bly reduced, and the vapor compressed, without any change 
of temperature, the compression has not the effect of aug- 
menting the pressure, as would happen if air was similarly 
treated, it only results in liquefying a portion of the 
steam, according as the volume is reduced, so that the 
volume, however reduced, will only contain so much pro- 
portionally the less of steam of the original pressure. In 
order to increase the pressure, the temperature must be 
raised. 

Point of Saturation of Steam. When the vapor has at- 
tained the limit of density and pressure, corresponding 
to the temperature, the steam is said to be saturated, and 
it is always in the state of saturation when in contact with 
water. For one pressure there is one density and one 



PROPERTIES OF STEAM 123 

temperature, and the higher the pressure, the greater is the 
density and the higher is the temperature. 

Expansion of Steam. When a quantity of steam is 
placed out of contact with water, as in the cylinder of a 
steam-engine, it may be expanded, and again compressed up 
to the limit of saturation, and it will follow approximately, 
though not precisely, the law of Boyle or Mariotte, that is 
to say, the pressure is nearly in the inverse ratio of the 
volume, insomuch that when the volume is doubled, the 
pressure is reduced to about one-half, and when the 
volume is trebled, the pressure is reduced to about a 
third. 

Superheated Steam. Superheated steam is amenable to 
the laws of permanent gases, and behaves as one of them, 
expanding and contracting in the inverse ratio of the 
pressure, when the temperature is constant, without the 
condensation of any portion of it. 

Density, Pressure, and Temperature of Steam. It fol- 
lows from the above, that one density and one pressure 
relative to one temperature are attained in a steam-boiler. 
These several qualities are in equilibrium, and the steam 
is in a state of saturation. That so long as the state of 
saturation corresponding to a given temperature is not 
attained, evaporation continues; and when attained, evapo- 
ration ceases. If the capacity of the boiler be increased, 
evaporation is resumed, until the state of saturation is 
again arrived at. Likewise, if the temperature be in- 
creased, evaporation is resumed, and continues till the 
steam again becomes saturated. If the temperature falls, 
the pressure and the density fall also. If the boiler be 
closed, and the steam remain at the same temperature, the 
conditions remain unchanged. But, if an opening be made 
for the outflow of steam, the pressure will fall, and evapo- 
ration will be recommenced, until saturation is re-estab- 
lished. This new generation of steam is very rapid, so 



124 MACHINE SHOP PRACTICE 

much so that the pressure does not sensibly vary between 
and during the charges of steam taken from the boiler for 
each stroke of the piston. 

Flow of Steam. 

It is known that gases and vapors act like liquids in 
flowing through tubes and orifices. The velocity of flow 
of liquids is given by the ordinary formula of gravity: 
which is 

V=i/2gh, or V=8v / h; 

in which V is the velocity in feet per second, g the velocity 
acquired by a body falling from a state of rest, at the end 
of one second, being 32.2 feet per second, and h the height 
in feet through which the body falls. The velocity acquired 
in falling through a given height, is equal to 8 times the 
square root of the height in feet, the product being the 
velocity expressed in feet per second. A modification of 
the same formula is applicable for calculating the flow of 
gases. There is this distinction, that while for liquids, the 
height through which the water falls, to the orifice of flow, 
can be easily ascertained by measurement, for gases it is 
necessary to ascertain the height by calculation. 

The Pressure of Gas or vapor is equal to that of a 
column of the gas of which the weight is equal to the 
pressure, and if the pressure per square inch be divided by 
the weight of a prism of the gas, one inch square and one 
foot high, the quotient is the height in feet of the equiva- 
lent column of gas, from which the velocity of flow is to 
be calculated. The velocity so calculated applies to the 
discharge of the gas into a vacuum. But, under ordinary 
circumstances, a counter-pressure exists, being the pressure 
of the medium into which the gas is discharged, and the 
value of the counter-pressure has to be deducted from the 
total pressure, when the difference, the net pressure of 



PROPERTIES OF STEAM 125 

the column is to be calculated. The head is expressed by 
the formula, h=(P — p)-f-a, in which h is the head of 
height of the column, P and p are the total pressures per 
square inch of the gas and the medium into which it flows, 
and d is the density or weight of a prism of the gas, one 
inch square and one foot high. 

The application of the formula for gravity is limited to 
cases in which the resisting pressure does not exceed 
about 58 per cent, of the absolute pressure which causes 
the flow. The flow is neither increased nor diminished by 
reducing the resisting pressure below about 58 per cent, of 
the absolute pressure in the boiler. For example, the same 
weight of steam would flow from a boiler under a total 
pressure of 100 pounds per square inch into steam of 58 
pounds total pressure, as into the atmosphere. 

Velocity of Efflux of Steam. The following are a few 
examples of the velocity of efflux of steam of absolute 
pressure, varying from 25.37 pounds to 100 pounds per 
square inch, into the atmosphere, the velocity being cal- 
culated as for steam of the initial density, unexpanded. 



Total Pressure in Pounds per square 
inch. 


Velocity of Efflux in Feet per secoud. 


25 37 


863 


30 


867 


45 


877 


60 


885 


75 


891 


100 


898 



Velocities thus calculated in terms of simple pressure 
and density, are of course greater than are arrived at in 
practice, as "^here are sundry hindrances to the flow of 
steam in steam-engines. There is, however, ample margin, 
and in well-constructed engines the speed of the actual 
flow of steam, though much below what it would attain if 



126 MACHINE SHOP PRACTICE 

the flow were free, is, nevertheless, sufficiently rapid for 
the proper performance of the steam in passing into and 
passing out of the engine. To reduce as much as. possible 
the effects of contraction and friction in retarding the flow 
of steam, it is necessary to observe the following precau- 
tions. To reduce as much as possible the lengths, and in- 
crease the sectional areas, of the pipes and passages 
through which the steam is to pass. To avoid sudden 
changes of direction in the parts or passages. To obtain 
the steam as dry as possible. 

Lead of the valve. If the lead of the valve is too late 
the maximum pressure of the steam in the cylinder is not 
attained until after a portion of the stroke is traversed 
by the piston. When the lead of the valve is too early, 
the steam is admitted so readily as to be momentarily 
compressed, and to cause, in some cases, an unfavorable 
pulsatory action of the steam. The total absence of lead 
of the valve likewise occasions an unsteady pulsatory 
action of steam in the cylinder. 

It is important to use dry steam, because, when the 
steam is condensed within the cylinder, or if it be loaded 
with water by priming, it causes back-pressure and loss 
of power. 

Absolute Temperature. 

The zero of temperature on the Centigrade and Fahren- 
heit scales has been chosen arbitrarily, on one the zero 
being the freezing point of water, and on the other a point 
32 degrees Fahrenheit below it. 

For scientific purposes it is necessary to have a uniform 
zero, and such a point, called the zero of absolute tem- 
perature, has been chosen, the position of which is 461 
degrees Fahrenheit, below the zero Fahrenheit, or 273 de- 
grees Centigrade, below the zero Centigrade. 

Hence to express degrees Fahrenheit in degrees of abso- 



PROPERTIES OF STEAM 127 

lute temperature, add 461. Thus the boiling point of water 
at atmosphere pressure=212 degrees Fahrenheit=212-f461 
=673 degrees absolute temperature. 

To convert degrees Fahrenheit into degrees Centigrade: 

Subtract 32, multiply the remainder by 5, and divide 
by 9. 

Thus, convert 158 degrees Fahrenheit to degrees Centi- 
grade. 

Then (158—32) f = 70 degrees Centigrade. 

Or, to convert degrees Centigrade into degrees Fahren- 
heit: 

Multiply by 9, divide by 5, and add 32. 

Thus, convert 70 degrees Centigrade into degrees Fahren- 
heit. 

Then (70 X |) +32= 158 degrees Fahrenheit. 

Specific Heat. 

The ratio of the amount of heat required to raise the 
temperature of a substance one degree to the amount of 
heat required to raise an equal weight of water one de- 
gree is called the specific heat of the substance. 

The specific heat of bodies varies very considerably, as 
will be seen from the following table: 
Water=1.000 Wrought lron=0. 113 Lead=0.031 

Cast Iron=0.130 Copper=0.100 Mercury=0.333 

Steel=0.118 Bismuth=0.031 Coal=0.241 

Water has the highest specific heat of any substance ex- 
cept hydrogen, and the metals have the lowest. In other 
words it takes more heat to raise the temperature of a 
given weight of water than any other substance. 

Heat. 

If one pound of cold water be heated in a closed vessel 
till the water becomes warm, although the temperature of 
the water has changed, its weight remains the same; and if 



128 MACHINE SHOP PRACTICE 

the heat be continued until all the water is converted into 
steam, provided none of the steam can escape, the total 
weight of the steam is still exactly the same as that of the 
water from which it is produced. 

It is evident, therefore, that the heat which produced 
these changes is without weight. Heat cannot, therefore, 
be a material substance. It was formerly thought to be 
some kind of subtle fluid, which flowed from hot bodies 
into colder ones. This theory is no longer accepted, be- 
cause it was found that heat could be developed to an un- 
limited extent from cold bodies merely by rubbing them 
together. 

A piece of cold iron can be made red hot by hammering 
it. A carpenter's saw or machinist's chisel or turning tool 
soon get hot when a rubbing action or friction, is set up 
between the tool and the work, although they are all quite 
cold to begin with. 

All bodies are assumed to be composed of minute par- 
ticles called molecules, held together by mutual attraction 
or cohesion and these molecules are in a state of continual 
agitation or vibration. The hotter the body the more vig- 
orous the vibration of its constituent particles. In solid 
bodies the vibrations are limited in extent. If this' limit 
is exceeded, owing to addition of heat, cohesion is suffi- 
ciently overcome to enable the particles to move about 
freely and without restriction, and the solid has now be- 
come a liquid. On still continuing the heat, further sepa- 
ration of the molecules takes place, cohesion is completely 
overcome, and they fly off in all directions. The liquid 
then becomes a gas. 

The unit of heat is the amount of heat necessary to 
raise the temperature of one pound of water one degree 
Fahrenheit when the water is at its greatest density, 
namely, from 39 to 40 degrees Fahrenheit. 

The rate of transfer of heat from a hot body to a cold is 



PROPERTIES OF STEAM 129 

proportional to the difference of temperature between the 
two bodies. The greater the difference of temperature the 
greater the rate of flow of heat. 

The transfer of heat from one to the other may take 
place in any of the following ways: namely, by radiation, 
convection, or conduction. 

Heat is given off from hot bodies in rays which radiate 
in all directions in straight lines. The heat from the burn- 
ing coal in a furnace is transferred to the crown and sides 
of the furnace by radiation, it passes through the furnace 
plates by conduction and the water is heated by convection. 
The process by which heat passes from hotter to colder 
parts of the same body, or from a hot body to a colder 
body in contact with it, is called conduction. A bar of 
iron having one end placed in the fire soon becomes hot 
at the other extremity, the heat being conducted from par- 
ticle to particle throughout its entire length. 

A piece of burning wood can be held with the hand close 
to the burning part. Some bodies, therefore, conduct heat 
much more readily than others. 

Let water at 32 degrees Fahrenheit be heated in a closed 
vessel, such as an ordinary steam boiler, containing space 
for the accumulation of steam, and let heat be gradually 
applied. Then the temperature of the water will gradually 
rise to that corresponding to the pressure within the boiler, 
after which evaporation commences and steam is formed. 

As the heat is increased, the temperature, pressure, and 
density, or weight per cubic foot, of the steam increases in- 
definitely, so long as the strength of the boiler is not ex- 
ceeded and the relation between the temperature, pressure, 
and density always bears a certain fixed relation. 

If just sufficient heat is supplied as to maintain the tem- 
perature constant, the pressure and density remain constant 
also, and evaporation ceases. If a communication be opened 
between the boiler and engine, on escape of steam from the 



130 MACHINE SHOP PRACTICE 

boiler the pressure is momentarily reduced and re-evapora- 
tion commences rapidly. So long as the temperature is 
maintained, no sensible variation of pressure is noticeable 
in a boiler supplying steam to an engine. 



THE INDICATOR 



131 



The uses to which an indicator is generally applied may 
be briefly stated as follows: 

To obtain a diagram showing the condition or the be- 
havior of the gases in the cylinder of an engine, the 
promptness of the admission, the fall in pressure from 
heat losses, the extent and character of the expansion, the 
efficiency of the exhaust, the extent of the back pressure 
Mpon the piston and the amount of compression at the end 
*)f the stroke. 

To find the average effective pressure exerted by the 
iteam upon the piston, from which to calculate the Indi- 
cated horsepower of the engine. 

To determine whether the valves have sufficient area and 
also whether they are set correctly, by taking diagrams 
from the cylinder and noting the points of admission, cut- 
off, exhaust and compression. 

An indicator consists primarily of a small steam cylinder, 
containing a piston, and a spring to regulate the movement 
"if the piston according to the pressure. A pencil or record- 
ing device, carried by an arrangement of small rods and 
levers, constituting a parallel motion, by means of which 
the pencil reproduces the vertical movement of the indicator 
piston but exaggerated four or five times. A drum, to 
which a paper, called a card, is attached, and which re- 
ceives a partial forward and backward rotation on its axis 
by means of a reducing gear operated from the crosshead or 
other suitable part of the engine. 

By the combined vertical movement of the pencil and 
the horizontal movement of the paper or card, a closed 
figure is drawn which is called an indicator diagram. The 

133 



134 



MACHINE SHOP PRACTICE 



diagram as traced on the card by the pencil of the indi- 
cator, differs more or less from a theoretical diagram, 
but an actual indicator diagram is considered the more per- 
fect the closer it approaches the outlines of a theoretical 
diagram. 




Pig. 83. 

Figs. 83 and 84 show external and cross-sectional views 
of a new form of Indicator. This instrument is in some 
ways a departure from the ordinary steam engine indi- 



THE INDICATOR 



135 



eator. One difference is in the location of the piston fcpring. 
This has been removed from the cylindrical case near the 
piston to the outside, and is affixed above the moving parts, 




Fig. 84. 



where it will remain cool under all conditions of use. What- 
ever error arises from heat, as affecting the spring in the 
ordinary type of indicator, is not present in this instrument. 



136 MACHINE SHOP PRACTICE 

The other and more important difference lies in the size 
and shape of the piston. This piston is one square inch in 
area, and is in the form of a central zone of a sphere. It 
is attached by a rod directly to the upper part of the 
spring, and moves freely and without restraint notwith- 
standing there may be some eccentricity in the action of 
the spring. In other words, this piston serves as a uni- 
versal joint to take care of the torsional strains of the 
spring when it operates the pencil mechanism of the indi- 
cator. The pencil mechanism is connected to the piston by 
a ball and socket joint. 

This rod slides through a sleeve attached to the base of 
the pencil mechanism, and, moving in a vertical line, com- 
pels the pencil to move also in a vertical line. 

Any motion of the piston due to the movements of the 
spring which causes the spring rod to deviate, will not 
affect the pencil mechanism in its vertical path. The con- 
tact of the piston with the interior side of the cylinder is a 
line, and does not induce friction. The piston of an indica- 
tor is usually a short cylinder fitted to slide easily within 
another cylinder. This form of piston is usually about one 
half inch long, and in use will develop friction about its 
circumference. A piston made in this manner must resist 
and overcome if possible the eccentricities of the spring 
in action, even then there is a want of freedom, notwith- 
standing the use of devices to relieve the piston friction. 
This condition tending to error is recognized by engineers, 
and considered in the computations made of the diagram 
taken by the indicator. The freedom of the piston move- 
ment in the indicator illustrated dispenses with the neces- 
sity of the correction of these errors. 

Another feature is the adjustment of the pencil to any 
desired position on the drum by loosening the binding nut 
below the spring and screwing the spring upward or down- 
ward, carrying with it the entire pencil mechanism. When 



THE INDICATOR 137 

relocated and the binding nut screwed firmly into place, 
the pencil is firmly held in its new position. 

The Indicator Diagram gives the initial pressure in the 
cylinder before expansion takes place. It also indicates 
whether the volume of the charge is diminished during its 
admission to the cylinder. It indicates when the expansion 
begins and the average pressure of expansion during the 
stroke. It gives the terminal pressure at the opening of the 
exhaust. It shows the point of opening of the exhaust. It 
shows the rapidity of the exhaust. It indicates the back 
pressure on the piston due to the exhaust. It gives the 
average pressure during the stroke. 

The usual method of obtaining the average pressure from 
an indicator diagram is by ascertaining its area by means 
of an instrument known as a planimeter, which is used to 
calculate the area of irregular surfaces. By moving the 
tracing point attached to the planimeter over the irregular 
outline of the diagram, its area is obtained. The area of 
the diagram divided by its horizontal length, gives the 
mean vertical height or ordinate of the diagram. The ini- 
tial presurre in pounds as shown by the diagram multiplied 
by this mean ordinate, gives the average pressure in pounds 
per square inch during the entire piston stroke. 

For the purpose of ascertaining the average pressure, it 
is sometimes sufficiently accurate to calculate the mean or- 
dinate by means of vertical measurement lines, or ordinates, 
drawn upon the diagram, which should divide the diagram 
into any desired number of rectangular panels of equal 
width. The sum of the length of these vertical ordinates, 
divided by the number of the ordinates will give the mean 
ordinate required, which, multiplied by the initial pressure, 
will give the average pressure required. From this the in- 
dicated horsepower may readily be found by the use of For- 
mula 1 or 6— Horsepower of Steam Engines. 

Example: With 64.7 pounds average pressure calculated 



138 MACHINE SHOP PRACTICE 

from the indicator diagram taken from an engine of 5 
inches bore and stroke at 300 revolutions of the crank 
shaft per minute, what will be the indicated horsepower of 
the engine? 

Answer: The average effective pressure on the piston in 
pounds per square inch will be 64.7 less 14.7, which equals 
50 pounds. The area of the piston is 19.64 square inches 
and the total piston stroke 0.83 feet. As the speed is 300 
revolutions of the crank shaft per minute, then by Formula 
No. 1, if IHP be the indicated horsepower, then 
TXTX> 50X0.83X19.64X300 nAA , 

IHP== 55^55 =7 ' 44 horse P° wer ' 

By Formula No. 6, as the square of the diameter of the 

cylinder is 25, then, 

TTTTi 50X0.83X25X300 

IHP= TTTi^ =7.44 horsepower. 

42,000 * 

The expansion curves of indicator diagrams vary con- 
siderably, and they do not obey any definite law. They 
are the resultant effect of a variety of causes operating 
differently in different engines, and even in the same en- 
gine by change of conditions. 

An ideal indicator diagram is illustrated in Fig. 85. 

The release point D occurs just before the end of the 
stroke. With high-speed engines it is important to have an 
early exhaust, as the trouble is usually not to get the steam 
into the cylinder, but to get it out. 

The exhaust curve DE represents the fall of pressure 
which occurs in the cylinder when the exhaust port opens. 
A late opening to exhaust is a very grave defect in an in- 
dicator. 

The back-pressure line EF shows the amount of the 
pressure against the piston during its return stroke. In non- 
condensing engines the baek-pressure line coincides the more 
nearly with the atmospheric line, as the exhaust passages 
permit of a fr^e exit frr the steam. In condensing engines 



THE INDICATOR 



139 



this line coincides the more nearly with the zero line, as the 
condensing water temperature is lower, and as air leaks are 
absent. 

The compression curve FA commences from the point of 
closure F of the exhaust port. This point depends upon the 
amount of inside lap on the valve, and the angular ad- 
vance of the eccentric, and the nature of the curve will de- 
pend upon the pressure of the steam and upon the volume 
%j£ the clearance space. 




A 



Fig. 85. 

A— Point of Admission. AB— Admission Line. BC— Steam Line. CD— Ex 
pansion Curve. DE— Exhaust Curve. EF— Back-pressure Line. F— Point 3 
Closing Exhaust. FA— Compression Curve. X— Atmospheric Pressure Lin- 
D— Release Point 



HORSEPOWER OF STEAM ENGINES. 

The standard of horsepower is the amount of energy that 
will raise a weight of 33,000 pounds one foot high in a 
minute, or 550 pounds one foot high in one second. An 
engine or motor exerting one actual horsepower will raise 
a weight of 10 pounds 3,300 feet in one minute, but will 
require 10 minutes to raise 330,000 pounds one foot high. 

Horsepower is of three kinds: Calculated, actual or brake, 
and indicated horsepower. Calculated horsepower is al- 
ways greatly in excess of actual or brake horsepower, as 
heat and friction losses do not enter into consideration in 
the formulas used. 

Actual or Brake horsepower is obtained by the use of a 
Prony brake, so called after its inventor. This simple de- 
vice gives the actual energy in foot-pounds per minute, de- 
livered at the driving shaft. 

Indicated horsepower represents the actual thermo-dyna- 
mic (heat pressure) conditions within the engine cylinder, 
but does not take into account friction or other external 
power losses. 

The factors entering into the calculation of the horse- 
power of a steam engine are, the effective temperature of the 
steam in the cylinder as indicated by the average pressure 
throughout the piston stroke, the cubic contents of the 
cylinder, which are given by the length of the stroke and 
the area of the piston, and the number of working strokes 
or impulses per minute. 

The product of these factors, which is found by multiply- 
ing them together, will give the available energy in foot- 
pounds per minute. This product, divided by 33,000, gives 
the horsepower required. 

143 



144 MACHINE SHOP PRACTICE 

To ascertain the horsepower when the average pressure 
upon the piston in pounds per square inch is known. 

Find the area of the piston in square inches, by multiply- 
ing the square of its diameter by 0.7854. 

Find the total pressure in pounds on the piston by mul- 
tiplying its area by the average effective pressure in pounds 
per square inch. The average effective pressure is the aver- 
age pressure in pounds per square inch less 14.7, which 
must be deducted to allow for the atmospheric pressure 
against the piston. 

Find the useful piston travel in feet per minute by multi- 
plying twice the length of the piston stroke in feet by the 
number of revolutions per minute of the crank shaft, for a 
double-acting steam engine. Find the energy in foot pounds 
per minute by multiplying the total pressure in pounds on 
the piston by the useful piston travel in feet per minute. 

The horsepower may then be ascertained by dividing the 
energy in foot-pounds per minute by 33,000. 

While there are numerous formulas in use for calculating 
the horsepower of an engine, one of the most simple is as 
follows : 

PXLXAXN 
HP_ 33,000 (1) 

Where P is the average effective pressure in pounds per 
square inch, L twice the length of the piston stroke in feet, 
A the area of the piston in square inches and N the number 
of revolutions of the crank shaft per minute. 

Example: What horsepower will a steam engine of 4- 
inch bore and 6-inch stroke develop at 300 revolutions of 
the crank shaft per minute, cutting off at one-third stroke 
and having an initial pressure of 150 pounds per square 
inch? 

Answer: The average pressure from Table No. 12, cor- 
responding to 150 pounds initial pressure, with one-third 
cut-off, is 104.9 pounds. From this must be deducted 14.7 



HORSEPOWER 145 

pounds, which represents the back or atmospheric pressure 
in the case of a single expansion engine, giving 90.2 pounds 
as the average effective pressure per square inch on the 
piston. From Table No. 3 the area of a circle 4 inches in 
diameter is 12.57 square inches, and twice the length of the 
piston stroke, which is 6 inches, is equal to one foot, then 
xxx , 90.2X1X12.57X300 

HP= » =10 - 31 *"--• 

The following formulas, 2, 3, 4 and 5, are merely trans- 
positions of Formula 1, but will be found very useful in 
ascertaining the value of any one of the five factors in 
Formula 1, when the other four are known. 

v=S3 ' m L^ht (2) 

Where P is the average effective pressure on the piston 
in pounds per square inch. 

Example: What is the average effective pressure on the 
piston of an engine, with a cylinder 12 inches in diameter 
and piston stroke of 18 inches, the number of revolutions 
of the crank shaft being 100 per minute, and the horse- 
power 40? 

Answer: As the area corresponding to 12 inches diame- 
ter is 113.09, or in round numbers, 113, then formula 2. 

rX33,000 3X11 4 8 ° xl0() =38.9 pounds. 

To ascertain the required length of the piston stroke in 
feet, when the other terms in the equation are known: 

HP 
PXAXN 
Where L is equal to twice the piston stroke in feet. 

Example: An engine is required to develop 40 horse- 
power, with 38.9 pounds average effective pressure pei 
square inch on a piston 12 inches in diameter and a speed 
of the crank shaft of 100 revolutions per minute. What 
should be the length of the piston stroke? 



L=33,000 T , v/tW , T (3) 



146 MACHINE SHOP PRACTICE, 

Answer: The average effective pressure being 38.0 
pounds, then by Formula 3, 

L=33 > 00 tefkiir 3 - 0feet - 

Given a piston stroke of 18 inches. 

To find the required cylinder diameter, other conditions 
being as before stated: 

A=33 ' 000 5>§b (4) 

Where A is the area of the cylinder in square inches. 

Example: An engine is required to develop 40 horse- 
power with an average effective pressure on the piston of 
38.9 pounds per square inch. The length of the stroke is 
18 inches and the speed of the engine crank shaft is 100 
revolutions per minute, what should be the cylinder dia- 
meter? 

Answer: The area of the cylinder by Formula 4 is there- 
fore 

40 
A=38 - 000 38.9X3X100 = 113 - 1 SqUare incheS " 

And from Table No. 3 the nearest diameter corresponding 
to an area of 113.1 square inches is 12 inches. 

The speed of the crank shaft of an engine may be readily 
ascertained from Formula 5, that is, if N be the speed of 
the crank shaft of the engine in revolutions per minute, 
then 

TTP 

N=33 ' 00( fe<Ixl (5) 

Example: Wlhat should be the speed of the crank shaft 
of an engine with a cylinder of 12-inch bore and 18-inch 
piston stroke^ to develop 40 horsepower with an average 
effective pressure of 38.9 pounds per square inch on the 
piston ? 

Answer: The speed of the crank shaft of the engine in 



HORSEPOWER 147 

revolutions per minute by Formula 5, will therefore be 

40 
N=33,000— — — rr— — =100 revolutions per minute. 
38. 9X3X113 

The following formula may be used in place in Formula 
1, if so desired: 

TXT , PXLXD 2 XN 

HF= 42,000 (6) 

Where D is the diameter of the piston in inches, the re- 
mainder of the terms used being the same as in Formula 1. 

Example: Calculate the horsepower of the same engine 
by formula 6. 

Answer: As the square of the diameter of the piston is 

4X4=16, then 

___ 90 .2X1X16X300 

HP= J^~ririf\ =10.31 horsepower. 

On the basis of these formulas, two simple rules may be 
derived for calculating the horsepower of a steam engine: 

1. The horsepower is equal to the average effective pres- 
sure in pounds per square inch, multiplied by twice the pis- 
ton stroke in feet, by the area of the piston in square 
inches and by the number of revolutions of the crank 6haft 
per minute, divided by 33,000. 

2. The horsepower is equal to the average effective pres- 
sure in pounds per square inch, multiplied by twice the pis- 
ton stroke in feet, by the square of the diameter of the pis- 
ton in inches and by the number of revolutions of the crank 
shaft per minute, divided by 42,000. 

It should always be borne in mind that 14.7 pounds must 
in any case be deducted from the average pressure to obtain 
the average effective pressure on the piston, whether the 
average pressure is obtained from an indicator diagram, 
from Table No. 12, or from Formula 2. 

Squares of diameters and areas of circles, are given in 
Tables No. 1 and 3. These may be used in connection 
with Formulas 1 to 6. 



148 



MACHINE SHOP PRACTICE 



Table No. 12 — Average Steam Pressure on Piston, 


in Pounds per Square Inch. 


Average Pressure 

throughout the 

Piston Stroke. 

Initial Pressure 

— 1. 


.966 


.937 


.919 


.846 


.743 


.699 


.596 


.385 


Number of 

Volumes to which 

ztie Steam is 

Expanded. 


1* 


H 


If 


2 


21 


3 


4 


8 


Point of Cut-off. 


3 


¥ 


5 
¥ 


i 


3 

¥ 


i 

¥ 


i 

4 


i 

¥ 




50 


48.2 


46.7 


45.9 


42.3 


37.1 


35.0 


29.8 


19.2 




55 


53.0 


51.3 


50.5 


46.6 


40.8 


38.4 


32.8 


21.2 




60 


57.8 


56.0 


55.1 


50.8 


44.5 


41.9 


35.8 


23.1 




65 


62.8 


60.7 


59.7 


55.0 


48.2 


45.4 


38.8 


24.9 


8 

08 


70 


67.4 


65.3 


<H.3 


59.2 


52.4 


48.9 


41.6 


26.7 





75 


72.3 


70.0 


o3.9 


63.5 


56.1 


52.4 


44.7 


28.6 


GO 


80 


77.1 


75.7 


73.5 


67.7 


59.3 


55.9 


47.7 


30.8 


0> 
P. 
QQ 


85 


81.9 


80.3 


78.1 


72.0 


63.0 


59.8 


50.7 


32.7 


3 


90 


86.7 


84.0 


82.7 


76.2 


66.8 


62.9 


53.7 


34.6 


o 


95 


91.5 


88.7 


87.3 


80.4 


70.4 


66.4 


56.7 


36.6 


a 


100 


96.4 


93.3 


91.9 


84.6 


74.2 


69.9 


59.6 


38.5 


3 


105 


101.2 


98.0 


96.5 


88.9 


77.9 


73.4 


62.6 


40.4 


to 

03 


110 


106.0 


101.7 


101.0 


93.1 


81.6 


76.9 


66.6 


42.3 


115 


110,8 


106.3 


105.6 


97.4 


85.2 


80.4 


69.6 


44.2 


o3 


120 


115.6 


112.0 


110.2 


101.6 


89.0 


83.9 


71.6 


46.2 


j Init 


125 


120.5 


115.7 


114.8 


105.8 


102.8 


87.4 


74.6 


48.1 


1 


2 


3 


4 


5 


6 


7 


8 



HORSEPOWER 



149 



Table No. 12 Continued — Average Steam Pressure 
on Piston, in Pounds per Square Inch. 


Average Pressure 

throughout the 

Piston Stroke. 

Initial Pressure 

=1. 


.966 


.937 


.919 


.846 


.743 


.699 


.596 


.385 


Number of 

Volumes to which 

the Steam is 

Expanded. 


n 


H 


H 


2 


2! 


3 
i 

3" 


4 


8 


Point of Cut-off. 


3 

4 


2 


¥ 


i 


3 

"8" 


i 

4 


"S" 


o 
d 

Ml 

O 
Sh 

oS 

o 4 

GO 
u 

<D 

Ph 
GO 

CI 
13 
O 

Ph 

a 

0> 

CO 
GO 

<D 

*H 
MH 

"43 

'2 


130 
140 
150 
160 

170 
180 
190 
200 

210 
220 
230 
240 

250 

260 
280 
300 


125.3 
134.9 
144.6 
154.2 

163.8 
173.5 
183.1 
192.8 

202.4 
212.0 
221.6 
231.3 

240.9 
250.6 
269.8 
289.1 


121.3 
130.7 
139.3 
151.3 

160.7 
168.0 
177.3 
186.7 

195.0 
203.3 
212.7 
224.0 

233.3 
242.7 
261.3 

280.0 


119.4 
128.6 
137.8 
147.0 

156.2 
165.4 
174.5 

183.8 

192.9 
202.1 
211.3 
220.5 

229.7 
238.9 
257.2 
275.6 


110.0 
118.5 
126.5 
135.4 

143.9 
152.4 
160.8 
169.3 

177.8 
186.2 
194.7 
203.2 

211.6 
220.1 
237.0 
254.0 


96.4 

103.8 
111.3 
118.7 

126.1 
133.5 
140.9 
148.4 

154.8 
163.2 
170.4 
178.1 

185.4 
192.9 
207.7 
222.5 


90.9 

97.9 

104.9 

111.8 

118.8 
125.8 
132.8 
139.0 

146.8 
153.8 
160.8 
167.8 

174.7 

181.8 
195.7 
208.7 


77.5 

85.3 
89.5 
95.4 

101.4 
107.4 
113.3 
119.3 

125.3 
133.2 
139.2 
143.2 

149.1 
155.1 
170.6 
179.0 


59.8 
53.9 
57.7 
61.6 

65.4 
69.3 
73.1 
77.0 

80.8 
84.6 
98.5 
92.4 

96.2 

99.7 

107.8 

115.5 


1 


2 


3 


4 


5 


6 


7 


8 



150 MACHINE SHOP PRACTICE 

HORSEPOWER OF GAS AND GASOLINE ENGINES. 

As the formulas used for the calculation of the horse- 
power of steam engines are not as a rule directly applicable 
to gas and gasoline engines, formulas are here given that 
will be found better suited to the purpose. 

From a theoretical standpoint a two-cycle engine should 
not only have as great a speed as a four-cycle engine, but 
should be capable of developing almost twice the power. It 
is a fact, however, that in actual practice the performance 
of a two-cycle engine is far different. 

The horsepower of a two or four-cycle engine may be 
calculated from the following formulas: 

HP=^!^(Two-cycle). (1) 

21,000 J 

Where D is the diameter and S the stroke of the piston in 
inches, N the number of revolutions of the crank shaft per 
minute and HP the required horsepower. 

Example: Required the horsepower of a two-cycle engine 
of 6 inches bore and stroke at 600 revolutions of the crank 
shaft per minute? 

Answer: The square of the bore multiplied by the stroke 
is equal to 216, which multiplied by 600 and divided by 
21,000, gives 6.17 as the required horsepower, or by For- 
mula 1. 

TTT , 36X6X600 a," 

HP= —=6.17 horsepower. 

For a four-cycle engine, the formula is: 

HP= i|i? (Fo,ir - cycle) - (2) 

Example: What horsepower should be developed by a 
four-cycle engine of 6 inches bore and stroke at 600 revolu- 
tions of the crank shaft per minute? 

Answer: As the bore and stroke of the engine are like, 
the square of the bore multiplied by the stroke is equal to 



HORSEPOWER 151 

the cube of 6, which is 216, this multiplied by 600, and 
divided by 18,000, gives 7.20 as the horsepower of the 
engine, or by Formula 2, 

TTT , 216X600 „ ortl 
HP=— t: — —=7.20 horsepower. 
18,000 F 

A four-cycle gas or gasoline engine has only one working 
stroke or impulse for each two revolutions of the crank 
shaft. During these two revolutions which complete the 
cycle of the engine, six operations are performed: 

1. Admission of an explosive charge of gas or gasoline 
vapor and air to the cylinder of the engine. 

2. Compression of the explosive charge. 

3. Ignition of the compressed charge by a hot tube or an 
electric spark. 

4. Explosion or extremely sudden rise in the pressure of 
the compressed charge, from the increase in temperature 
after ignition. 

5. Expansion of the burning charge during the working 
stroke of the piston of the engine. 

6. Exhaust or expulsion of the burned gases from cylin- 
der of the engine. 

As pressure increases with a rise in temperature, which 
in a gas or gasoline engine the moment after ignition has 
taken place is about 2,700 degrees Fahrenheit, the higher 
the temperature of the ignited gases, the greater would be 
the pressure. As this pressure is expended in work on the 
piston of the engine, the whole of it might, if expansion of 
the burning gases were continued long enough, be utilized. 
Full utilization of the expansion of the bases is however 
impossible from a mechanical standpoint. The expansion 
of the gases should be as rapid as possible, as the faster 
the piston uncovers the cylinder wall, the less time will be 
left for the transmission of heat or energy to the cylinder 
wall. Gasoline vapor or gas, in themselves are not com- 
bustible, but must be mixed with a certain amount of air 



152 MACHINE SHOP PRACTICE 

before ignition and consequent combustion of the charge 
can be effected. The combustion of the gases is not in- 
stantaneous as might be imagined, but continues during the 
entire working stroke of the piston of the engine. The ex- 
tremely high temperature produced by the combustion ne- 
cessitates the use of a cooling device round the exterior of 
the cylinder of the engine in the form of a water jacket. 

Gr'as and gasoline possess many advantages over steam 
engines, and compare favourably with them as regards the 
cost of fuel. 

Electrical Horsepower. One electrical horsepower is 
equal to the current in amperes multiplied by the electro- 
motive force or voltage of the circuit and divided by 746. 

Let C be the current in amperes and E the voltage of the 
circuit. If EHP be the required electrical horsepower, then 

EH Hf ■<» 

Example: What is the electrical horsepower of a 200- 
volt motor, which takes a current of 80 amperes? 

Answer: As the voltage is 200 and the current 80 am- 
peres then by Formula 1, 

200X80 
EHP= =21.44 horsepower. 

746 

One electrical horsepower is also equal to 746 watts. 

If C be the current in amperes, E the electro-motive force 
or voltage, R the resistance, and EHP the electrical horse- 
power, then 

CX.E_ E* 
EHP_ 746~746XR (2) 

In practice with motors or small power, 1,000 watts are 
necessary to deliver one mechanical or brake horsepower 
at the driving shaft of the motor. 

If the actual or brake horsepower of an electric motor be 
known, the efficiency of the motor may be readily found by 
the following formula: 



HORSEPOWER 153 

If E be the voltage of the circuit and C the current in 
amperes consumed by the motor, let BHP be the brake 
horsepower of the motor and e the efficiency of the motor, 
then 

BHPX746 



EXC 



(3) 



Example: What is the mechanical efficiency of a 200- 
volt motor, which when taking a current of 80 amperes, 
shows on a brake-test, 17.16 horsepower? 

Answer: As the brake horsepower is 17.16, the voltage 
200 volts, and the current 80 amperes, then by Formula 3, 

17.16X746 M 

e= 200X80 =8 ° perCent ' 

HORSEPOWER OF GEAR WHEELS. 

1. When the circular pitch is given— to find the horse- 
power capable of being transmitted by cast iron gears with 
cut teeth: Multiply the pitch diameter of the gear by the 
circular pitch of the teeth, by the width of the teeth, (all in 
inch measurements), and by the number of revolutions of 
the gear per minute. Divide the product by 550 and the re- 
sult will be the horsepower the gear is capable of trans- 
mitting. 

Let D be the pitch diameter of the gear, C the circular 
pitch and E the width of the tooth, (all in inch measure- 
ments, R the number of revolutions of the gear per minute 
and H. P. the horsepower the gear is capable of transmit- 
ting, then 

Hp= DX^XR 
5o0 

Example: What horsepower will the following cast iron 
gear with cut teeth transmit at 100 revolutions per minute? 
The circular pitch of the gear is 2 inches, the number of 
teeth- 33 and the width of the face of the tooth 2 inches. 



154 MACHINE SHOP PRACTICE 

Answer: As the pitch diameter of the gear is approx- 
imately 21 inches, then 

21X2X2X100 
550 
Note: A cast iron gear with cut teeth of 1 inch circular 
pitch and 1.048 inches width of tooth and with 33 teeth will 
transmit 1 horsepower at 50 revolutions per minute. As 
the pitch diameter of the gear approximately lO 1 /^ inches, 
then 

10.5X1X1.048X50 . u 

• — — =1 horsepower. 

550 

2. When the diameter pitch is given to find the horse- 
power capable of being transmitted by cast iron gears with 
cut teeth: Multiply the pitch diameter of the gear by the 
width of the tooth (both in inch measurements), and by 
the number of revolutions of the gear per minute. Divide 
the product by the Diametral pitch and by 175, and the re- 
sult will be the horsepower the gear is capable of trans- 
mitting. 

Let D be the pitch diameter of the gear, F the width of 
the tooth (both in inch measurements), R the number of 
revolutions of the gear per minute of the gear, P the dia- 
metral pitch and H. P the horsepower, then 

DXFXR 
HF PX175 (2) 

Example: What horsepower will the following cast iron 

gear with cut teeth transmit at 100 revolutions per minute? 

The diametral pitch of the gear is V/ 2 , the width of the 

face of the tooth 2 inches, and the pitch diameter 20 inches. 

Answer: 20X2X100 '„, , 

——7—— =15.24 horsepower. 
1.5X175 

3. To find the horsepower capable of being transmitted 
by a gear with cut teeth of any given material. Multiply 
the results obtained by. Rule 1 or 2, or by Formula 1 or 2, 
by the coefficients for the various metals given herewith.:. 



THE INDICATOR 155 

Cast iron being taken as 1 or unity, then: Malleable 
Iron=1.25, Brass=1.33, Bronze=1.66, Gun Metal=2.00, 
Phosphor Bronze=3.00, Wrought Iron=3.33, Steel=4.00. 

Example: If a cast iron gear of given dimensions will 
transmit 2 horsepower, what horsepower will a similar gear 
if made of phosphor bronze? 

Answer: As the coefficient for phosphor bronze is 3, 
then 2X3=6 horsepower that the gear will transmit if 
made of phosphor bronze in place of cast iron. 

Note: If the diametral instead of the circular pitch be 
given. To find the circular pitch of the teeth, divide 
3.1416 by the diametral pitch of the gear. 

Example: Required the circular pitch of the teeth of a 
gear of 4 diametral pitch? 

Answer: 3.1416 divided by 4, gives .7854 as the circular 
pitch in inches of the gear teeth. 

Example: What is the circular pitch of a gear of 2 
diametral pitch? 

Answer: 3.1416 divided by 2, gives 1.5708 inches as th« 
circular pitch of the gear teeth. 



ELECTRICITY 



Electricity or electrical energy may be generated in sev- 
eral ways: Mechanically, by means of a dynamo, and stati- 
cally or by friction. By whatever means it is produced, 
there are many properties which are common to all. There 
are also distinctive properties. The current supplied by a 
storage battery will flow continuously until the battery is 
practically exhausted, while the current from a dry bat- 
tery can only be used intermittently: that is, it must have 
slight periods of rest, no matter how short they may be. 

Electrical Rules and Formulas. Force is any cause of 
change of motion of matter. It is usually expressed by 
volts, pounds or other units. 

Resistance is a counter-force or whatever opposes the 
action of another force. 

Work is force exercised in traversing or crossing a space 
against a resistance of counter-force. Force multiplied 
by space or distance represents work in foot-pounds. 

Energy is the capacity for doing work, and is measured 
by the work done. 

The cause of a manifestation of energy is force. If this 
be electro-motive energy or electric energy in current form 
it is called Electro-motive force. The practical unit of 
electro- motive force is the Volt. 

When electro-motive force does work in a closed electric 
circuit a current is produced. The practical unit of current 
is called the Ampere. 

A current of electricity, when flowing in a closed electric 
circuit, passes through some substances more easily than 
through others. 

The relative ease of passage of the electric current is 
known as conductive. In practical calculations its recip- 

159 



160 MACHINE SHOP PRACTICE 

rocal, which is called resistance, is generally used. This 
practical unit is known as the Ohm. 

A current of one Ampere is maintained by one Volt 
through a resistance of one Ohm. 

Ohm's Law may be generally stated under the following 
heads : 

The current is in direct proportion to the voltage of the 
circuit, and inversely proportional to its resistance. 

1. The current is equal to the voltage divided by the re- 
sistance of the circuit. 

2. The voltage is equal to the current multiplied by the 
resistance of the circuit. 

3. The resistance of the circuit should equal the voltage 
divided by the current required. 

Let C be the current in amperers flowing in the closed 
electric circuit, and E the electro-motive force or voltage of 
the circuit, if R be the resistance in Ohm's of the circuit 
when closed, then 

C=| (1) 

E = CXR (2) 

E=| (3) 

Example: What will be the current flowing in a closed 
electric circuit with an electro-motive force of 50 volts and 
a resistance of 2 Ohms? 

Answer: By Formula 1, the current will be 50 divided 
by 2, which gives 25 amperes. 

Example: What must be the voltage of an electric cir- 
cuit to force 25 amperes through 2 Ohms resistance? 

Answer: From Formula 2, the voltage will equal- 25 
multiplied by 2, or 50 volts. 

Example: Through what amount of resistance will an 
electro-motive force of 50 volts, force a current of 25 am- 
peres ? 



ELECTRICITY 161 

Answer: By formula 3, 50 divided by 25 equals 2 Ohms 
as the required resistance. 

Ampere-hour. The term ampere-hour is used to denote 
the capacity of a storage of a closed-circuit primary bat- 
tery for current. A storage battery that will keep a 2 
ampere lamp burning for 8 hours is said to have a 16 am- 
pere-hour capacity. In a similar manner an 80 ampere-hour 
battery would operate the same lamp 40 hours. The voltage 
of a battery does not enter into the calculation of its am- 
pere-hour capacity. 

Watt-hour. A current of one ampere flowing in a closed 
electric circuit, with an electro-motive force of one volt, is 
equal to one volt-ampere or one watt. The voltage of a 
circuit, multiplied by the rate of the current flowing in 
amperes, gives the rate of work, or energy expended in 
watt-hours. 

An electro-motive force of one volt, with a current 
strength of one ampere, is capable of developing an amount 
of work or energy called a watt. 

4. One volt multiplied by one ampere is therefore equal 
to one watt. 

5. The square of current multiplied by the resistance is 
also equal to the number of watts. 

6. The square of the electro-motive force or voltage, 
divided by the resistance is also equal to the watts. 

Let E be the electro-motive force of an electric circuit 
supposed close. If C be the current in amperes, R the re- 
sistance in Ohms and W the watts, that is the product of 
the Volts multiplied by the Amperes, then 

W =EXC (4) 

= C 2 XR (5) 

-5 

Example: What is the rate of work or energy of an 



162 MACHINE SHOP PRACTICE 

electric circuit, which has an electro-motive force of 50 
volts and a current of 25 amperes'? 

Answer: By Formula 4, the energy is 50 multiplied by 
25, or 1250 watts. 

Example: With a current of 25 amperes and a resis- 
tance of 2 Ohms, what is the rate of work or energy in 
the circuit in watts. 

Answer: From Formula 5, the work or energy in the 
circuit is equal to 25X25X2=1250 watts. 

Example: What is the rate of work or energy in an 
electric circuit having an electro-motive force of 50 volts 
and a current of 25 amperes. 

Answer: By Formula 6, the rate of work or energy is 
50X50 divided by 2, or 1250 watts. 



MEASURING DEVICES 



163 



If a machinist wishes to become a first class workman he 
must learn to thoroughly understand the necessity of close 
or accurate measurements. With the aid of a micrometer 
he will soon learn to detect the difference between one- 
half and one-thousandth of an inch, and will then begin 
to appreciate the value of delicate or fine measurements and 
accurate workmanship. 

At the present time when the making of interchangeable 
parts for machinery is an established factor in all large 
shops, the fitting of one part to another is no longer a 
question of guesswork, but of working to gauges and tem- 
plets, the absolute sizes of which are definitely fixed. Hence 
the necessity for accurate measuring devices as are here- 
with illustrated, which were formerly to be found only in 
a few large shops. 

Micrometers. 

Micrometers form convenient and accurate instruments 
for fine external measurements. They are made in different 
sizes and styles to measure all sizes. They are graduated 
to read to thousandths of an inch, and one-half and one- 
quarter thousandths are readily estimated. Some microme- 
ters have verniers by which sizes can be obtained to ten- 
thousandths. 

The gauge screws are encased and protected from dirt 
and liability to injury. The parts most subject to wear 
are hardened and means of adjustment are provided to 
compensate for wear of the screw or nut. The decimal 
equivalents stamped on the frame are very convenient and 
render possible the immediate expression of readings in 
eights, sixteenths, thirty-seconds and sixty-fourths of on 
inch. 

165 



166 



MACHINE SHOP PEACTICE 




Fig. 86. 
The chief mechanical principle embodied in the construc- 
tion of a micrometer is that of a screw free to move in a 



MEASURING DEVICES 



167 



fixed nut. An opening, to receive the work to be measured, 
is afforded by the backward movement of the screw and 
the size of the opening is indicated by the graduations. 




Fig. 87. 

A standard form of micrometer is shown in Fig. 86 which 
will measure up to 1 inch by one-thousandths of an inch. 



168 



MACHINE SHOP PRACTICE 



Fig. 87 illustrates a micrometer with removable anvils for 
quick changes of measurements. 

How to Read a Micrometei 

The spindle C, Fig. 88, is attached to the thimble E at 
the point H. The part of the spindle which is concealed 
within the sleeve and thimble is threaded to fit a nut in 
the frame A. The frame being held stationary, the thim- 
ble E is revolved by the thumb and finger, and the spindle 
C being attached to the thimble revolves with it, and 
moves through the nut in the frame, approaching or re- 




Pig. 88. 



ceding from the anvil B. The article to be measured is 
placed between the anvil B and the spindle C. The mea- 
surement of the opening between the anvil and the spindle 
is shown by the lines and figures on the sleeve D and the 
thimble E. 

The pitch of the screw threads on the concealed part 
of the spindle is. 40 to an inch. One complete revolution 
of the spindle therefore moves it longitudinally one fortieth 
(or twenty-five thousandths) of an inch. The sleeve D is' 
marked with 40 lines to the inch, corresponding to the num- 
ber of threads on the spindle. When the micrometer is 
closed, the beveled edge of the thimble coincides with the 



MEASURING DEVICES 169 

line marked on the sleeve, and the line on the thimble 
agrees with the horizontal line on the sleeve. Open the 
micrometer by revolving the thimble one full revolution, or 
until the line on the thimble again coincides with the 
horizontal line on the sleeve. The distance between the 
anvil B and the spindle C is then 1-40 (or .025) of an inch, 
and the beveled edge of the thimble will coincide with the 
second vertical line on the sleeve. Each vertical line on the 
sleeve indicates a distance of 1-40 of an inch. Every fourth 
line is made longer than the others, and is numbered 0, 1, 
2, 3, etc. Each numbered line indicates a distance of four 
times 1-40 of an inch, or one tenth. 

The beveled edge of the thimble is marked in twenty- 
five divisions, and every fifth line is numbered, from 
to 25. Rotating the thimble from one of these marks to 
the next moves the spindle longitudinally 1-26 of twent} r - 
five thousandths, or one thousandth of an inch. Rotating 
it two divisions indicates two thousandths, etc. Twenty- 
five divisions will indicate a complete revolution, .025 or 
1-40 of an inch. 

To read the micrometer, therefore, multiply the number 
of vertical divisions visible on the sleeve by 25, and add 
the number of divisions on the bevel of the thimble, from 
to the line which coincides with the horizontal line on the 
sleeve. For example, as the tool is represented in the en- 
graving, there are ten divisions visible on the sleeve. Multi- 
ply this number by 25, and add the number of divisions 
shown on the bevel of the thimble, which is 10. The 
micrometer is therefore open two-hundred and sixty-thou- 
sandths. (10X25=250-f-10=:260). 

How to Read a Micrometer to Ten-Thousandths. 

Readings in ten thousandths of an inch are obtained by 
the use of a vernier, so named from Pierre Vernier, who 
invented the device in 1631. As applied to a micrometer 



170 



MACHINE SHOP PRACTICE 



this consists of ten divisions on the adjustable sleeve, which 
occupy the same space as nine divisions on the thimble. 
The difference between the width of one of the ten spaces 
on the sleeve and one of the nine spaces on the thimble is 
therefore one tenth of a space on the thimble. In Fig. 89 




THIMBLE 

O io o 



11 



03876 54 3210 

SLf.EVe 



4- -Ui 



HI 1,1 1,1 II 



09876543 210 
SLEEVE 



B 



A 



Fig. 89. 



at A the third line from on thimble coincides with the 
first line on the sleeve. The next two lines on thimble and 
sleeve do not coincide by one tenth of a space on thimble. 
The next two, marked 5 and 2, are two tenths apart, and 
so on. In opening the micrometer, by turning the thimble 
to the left, each space on the thimble represents an open- 
ing of one thousandth of an inch. If therefore the thimble 
be turned so that the lines marked 5 and 2 coincide, the 
micrometer will be opened two tenths of one thausandth 
or two ten thousandths. Turning the thimble further, until 
the line 10 coincides with the line 7 on the sleeve, as in 
Fig. 89 at B, the micrometer has been opened seven ten 
thousandths and the reading is .2257. 

To read a ten thousandths micrometer, first note the 
thousandths as in the ordinary micrometer, then observe the 
line on the sleeve which coincides with a line on the thim- 
ble. If it is the second line, marked 1, add one ten thou- 
sandth; if the third, marked 2, add two ten thousandths, 
etc. 



MEASURING DEVICES 



171 



Screw Thread Micrometer. 

The mierometer shown in Fig. 90 is intended for the 
accurate measurement 
of V threads on screws, 
taps, thread gauges, 
etc., by measuring the 
actual thread. 

The distinctive 
feature in the construc- 
tion of this micrometer 
is that the end of 
the movable spindle 
is pointed and the 
tixed end or anvil is 
V shaped. Enough is 
taken from the end of 
the point and the bot- 
tom of the V is carried 

down low enough, so that they will not rest 
on the bottom or top of the thread to be 
measured but on the cut surface. As the 
thread itself is measured, it will be seen 
that the actual outside diameter of the 
piece does not enter into consideration. 

As only one-half of the depth of the 
thread from the top, on each side is 
measured, the diameter of the thread as 
indicated by the caliper, or the pitch diam- 
eter, is the full size of the thread less the 
depth of one thready 

This depth may be found as follows: 

Fig. 90. 

Depch of V threads = .866 ■+■ number of threads to 1 inch, 
" "U. S.Stdo " =.6495-*- " u " " " 
M " Whitworth " =.M -*- " " " ' " 




172 MACHINE SHOP PRACTICE' 

As the U. S. standard thread is flatted 1-8 of its own 
depth on top, it follows that the pitch diameter of the 
thread is increased 1-8 on each side, equaling 1-4 of the 
whole depth and instead of the constant .866 the constant 
.6495 in used, which is three-fourths of .866. 

While the movable point measures all pitches, the fixed 
anvil is limited in its capacity, for if made large enough 
to measure a 4 pitch thread is would be too wide at the 
top to measure a 24 pitch thread and if made to measure 
a 24 pitch thread it would be so small that the thread 
would not obtain a proper bearing in the anvil. Thus each 
micrometer is necessarily limited in the range of threads 
that the anvil can measure. 

Ratchet Stop for Micrometers. 

When using the device shown in Fig. 91, the ratchet slips 
by the pawl when more than a certain amount of pressure 




Fig. 91. 
is applied, and so prevents the measuring spindle from 
turning farther and perhaps springing the instrument. 

It is valuable where a number of measurements have to 
be taken quickly and especially where measurements are 
taken by more than one person with the same micrometer, 
as by its use the same amount of pressure is applied to the 
article to be measured, in every case. 

Sheet Metal Micrometer. 

The Micrometer shown in Fig. 92, is recommended as 
especially convenient for sheet metal workers. 



MEASURING DEVICES 



173 



By placing the middle finger of the right hand through 
the ring, the micrometer is readily held at right angles to 
the sheet to be measured and readings made while in this 
position. The thimble can be operated by the forefinger 
and thumb of the same hand. 




Fig. 92. 

The micrometer measures all sizes less than four-tenths of 
an inch by one-half thousandths of an inch, but one-quar- 
ter thousandths are readily estimated. 

To facilitate the reading of the micrometer while held 
in position, the one-half thousandths readings are taken 
from the dial at the top of the spindle, the readings being 
indicated by the pointer. The twenty-five thousandths 
readings, or those corresponding to the readings on the 
barrel of an ordinary Micrometer, are taken from the scale 
at the top of the frame. 

The decimal equivalents stamped on the frame are con- 
venient and render possible the immediate expression ot 
readings in 8ths, 16ths, 32ds and 64ths of an inch. 



174 



MACHINE SHOP PRACTICE 



Inside Micrometer Gauges. 

The Inside Micrometer Gauge, shown in Fig. 93, is de» 
signed for making internal measurements, as in measuring 
rings, cylinders, setting calipers, comparing gauges, and 



II 






IMS 



Pig. 93. 

work of a similar character. It is also well adapted for 
measuring parallel surfaces. 

The Gauge consists of a holder provided with a micro- 
meter screw and thimble. The screw has a movement of 
three-tenths of an inch; and, by the use of the extension 
rods furnished, measurements from 3 to 6 inches may be 
made bv thousandths of an inch. 



MEASURING DEVICES 



175 



The extension rods vary by inches, and should be read^ 
justed only when the point of the rod has become worn. 

Provision is made for adjustment to compensate for wear 
of the screw and measuring surfaces. The measuring Bur- 
faces are hardened. 




mm** 



uaa 



*^MI 



II I - 



« 



* 



Fig. 94. 



The micrometer gauge illustrated in Fig. 94 is designed 
for internal measurements of large cylinders and of dis- 
tances between uprights. The body of the tool is a steel 
tube provided with a binding chuck on each of its ends. 
Into one end is clamped a plain rod, which, when the chuck 
is loosened, can be quickly adjusted to any approximate 
size. Into the other end is screwed a threaded anvil for 
fine adjustment. 

To set the gauge it is only necessary to loosen the chuck 
that clamps the wire rod, slide the rod out or in to the 
required size, and clamp it. If not quite correct, loosen 
the chuck on the opposite end and turn the anvil out or in 
what little is needed. 

Caliper Gauges. 

The Caliper Gauge shown in Fig. 95 is hardened and 
ground accurately, one end for outside and the other for 
inside measurements. By their use, mistakes in the setting 
of calipers and variations in measurements may be in a 
great measure avoided. Their form gives lightness and 
strength, making them preferable to plugs and rings for 



176 



MACHINE SHOP PRACTICE 



frequent use. As furnishing convenient and reliable stand- 
ard sizes for every day use in the workshop, they are of 



Pig. 95 




is M 



MEASURING DEVICES 177 

great advantage and their use contributes to uniformity in 
the production of the working parts of machinery. 

Sizes larger than three inches are made in two parts 
for convenience in handling. 

Limit Gauges, 

The accurate production of duplicate parts, as required 
in the economical manufacture of machinery, tools, instru- 
ments, etc., demands accurate Gauges and, in order to 
secure the most economical production, Limit Gauges are 
necessary to avoid time being wasted in finishing the work 
unduly accurate and still leaving it so that two or more 
parts when brought together will fit sufficiently well to meet 
requirements. 

The advantages derived from the use of Limit Gauges 
are being appreciated more and more, as, by their use, the 
time consumed in testing and gauging is reduced to a mini- 
mum, and the duplication of parts is insured. 

The cuts shown in Fig. 96 represent the most common 
form of Internal and External Limit Gauges, 

The two ends of Gauges of this type are of different 
shape. The workman is thus enabled to easily and quickly 
distinguish the large from the small end without looking at 
the sizes stamped upon the Gauge. 

These Gauges are not only used as ref3rences for finish- 
ing operations but are of great advantage in roughing work 
for finishing. "When used in this way the same amount of 
stock is left on each piece, thus enabling the operator, who 
finishes the pieces, to work to better advantage than if they 
were of various sizes. 

Depth Gauges. 

The gauge shown in Fig. 97 is designed for measuring 
the depth of grooves, holes or irregular parts. It has a on*- 



178 



MACHINE SHOP PRACTICE 



half inch movement of the screw, reading in thousandths, 
and with two one-half inch and one 1 inch standard collars 
to slip off or on the spindle 2y 2 inches, reading in thou- 
sandths, can be obtained. The 
split nut is covered and protected 
by a graduated sleeve, which not 
only protects the nut from dirt, 
but provides a quick and accurate 
way of taking up wear and ad- 
justing the micrometer to insure 
correct reading. The sleeves, 
being held by a stiff friction, 
may be rotated by a spanner 
wrench, accompanying each 
gauge, so that the zero lines will 
always coincide for correct 
reading. 

The head carries with it a 
knurled set screw for locking 
the spindle to prevent changing 
after being set. 

The Depth Gauge 
shown in Fig. 98 is 
used to obtain the 
depth of holes, recesses 
in dies, distance from a 
plane surface to a projec- 
tion, etc. The blade is 
5 inches long and one- 
quarter wide and allows 
for measurements up to 
3y 2 inches being made, 




Fig. 97. 



and is graduated on the front to read, by means of a vernier, 
to thousandths of an inch. The back of the blade is grad- 
uated to 64th s of an inch. 



MEASURING DEVICES 



179 




Fig. 98. 

Surface Gauges. 

The Surface Gauge shown in Fig. 99 in admirably adapt- 
ed for large work. The sleeve and needle clasp, when 
loosened for adjustment, are both held by a slight spring 



180 



MACHINE SHOP PRACTICE 



friction, and by a single knurled nut both are rigidly 
clamped. For fine adjustment, the spindle in the base is 
raised or lowered by a knurled nut, and all backlash is 
taken up by a spiral spring in the base. 

For heights above 12 inches an extension rod is provided 
to couple on to the spindle. 




Fig. 100. 



Fig. 99. 



Fig. 100 illustrates a form of universal surfaee gauge 
which has a Y-shaped groove in one end and another in 
the base which makes it adaptable for use on circular work. 



MEASURING DEVICES 



181 




-A 






^1 xSBBp yia'"" 





Fig. 101. 

Fig. 101 illustrates some of the uses to which the surface 
gauge shown in Fig. 100 may be adapted. 



182 MACHINE SHOP PRACTICE 

The spindle jasses through a rotating- head, jointed to a 
rocking bracket, pivoted in base. This bracket is adjusted 
by a knurled screw in one end against a stiff spring in the 
other, the spindle may be set upright or at any angle, or 
turned so as to work under the base and be adjusted to 
any position. The snug and head carrying the scriber are 
so made, that when the clamp nut is loosened, all may be 
freely moved to any position and by friction springs re- 
tained in place until a slight turn of the clamp nut holds 
them firm. 

In the rear end of the base are two gauge pins fictional- 
ly held which may be pushed to bear against the edge of a 
surface plate or in the slot of a planer bed for line work. 

For small work the spindle may be removed and the 
scriber inserted in the hole provided for the purpose, where 
it may be adjusted and used to advantage on bench work. 

The Vernier Caliper and Its Use. 

On the bar of the Vernier Caliper shown in Fig. 102 is a 
line of inches numbered 0, 1, 2, etc., each inch being divid- 
ed into ten parts and each tenth into four parts, making 
forty divisions to the inch. On the sliding jaw is a line 
of division of twenty-five parts, numbered 0, 5, 10, 15, 20, 
25. The twenty-five parts on the Vernier correspond, in 
extreme length, with twenty-four parts or twenty-four 
fortieths of the bar, consequently each division on the Ver- 
nier is smaller than each division on the bar by one thou- 
sandth part of an inch. If the sliding jaw of the Caliper 
is pushed up to the other, so that the line marked on 
the Vernier corresponds with that marked on the bar, 
then the two next lines to the right will differ from each 
other by one thousandth or an inch and so the difference 
will continue to increase, one thousandth of an inch for 
each division, till they again correspond at the line marked 
25 on the Vernier. To read the distance the Caliper is 



MEASURING DEVICES 



183 



open, commence by noticing how many inches, tenths and 
parts of tenths, the zero point on the Vernier has been 
moved from the zero point on the bar. Now count upon the 
Vernier the number of divisions, until one is found which 
coincides with one on the bar, which will be the number 
of thousandths to be added to the distance read off on the 
bar. The best way of expressing the value of the divisions 
on the bar, is to call the tenths one hundred thousandths 
(.100) and the fourths of tenths, or fortieths, twenty-five 
thousandths (.025). Referring to Fig. 99, 102, it will be 





.1...1...1 ..i... . f. 



-0—5— 10-1-5-2 0-2S- 



Fig. 102. 

seen that the jaw is opened two-tenths and three quarters, 
which is equal to two hundred and seventy-five thousandths 
(.275). Now suppose the Vernier is moved to the right so 
that the tenth division would coincide with the next one 
on the scale, which will make ten thousandths (.010) more 
to be added to two hundred and seventh-five thousandths 
(.2*75), making the jaws open two hundred and eighty-five 
thousandths (.285). 



184 



MACHINE SHOP PRACTICE 



A form of Vernier Caliper is shown in Fig. 103 which is 
graduated on the front to read to thousands of an inch 
and on the back to 64ths of an inch. 




Fig. 103 



The Combination Bevel. 

The combination bevel shown in Fig. 104 has a stud rivet- 
ed in the straight edge stock or head, on which its split 
blade is hinged, so as to swing over the stock, and be 
clamped at any angle. The slotted auxiliary blade with 




Fig. 104. 
clamp bolt may be slipped on to the split blade and w 
clamped at any desired angle and used, in combination 
with the stock of the other, for laying out work, measuring, 
or showing any angle desired, and, when so combined, will 
lie flat upon its work. 



MEASURING DEVICES 



18! 




Pig. 105. 

Fig. 105 shows some of the many uses to which the com' 
bination bevel shown in Fig. 104 may be put. 



186 



MACHINE SHOP PRACTICE 



The Protractor, 

A universal bevel protractor is illustrated in Fig. 106, 
The disc is graduated in degrees from to 90 each way, 
and rotates the entire circle on a central stud inside the 
case. The blade which is clamped by an eccentric stud 
against the edge of the disc, may be slipped back and forth 
its full length, or turned at any angle around the circle and 
firmly clamped at any point, adapting it for work in posi- 
tions where others cannot be used, and rendering the com- 
mon universal bevel generally used for transferring angles 
unnecessary. One side of the stock being flat, makes it a 
convenient tool for laying on paper in drafting, and it has 
double the utility of any other tool of the kind. 




Fig. 106. 



The attachment shown in the smaller view in Fig. 106 
will be found very convenient for grinding worm thread 
tools, tapers on lathe centers, and all long tapers. 



MEASURING DEVICES 



187 




Fig. 107. 

Fig. 107 shows some of the various uses of the Universal 
bevel protractor, A form of bevel protractor is illustrated 



MACHINE SHOP PRACTICE 




Fig. 108. 



MEASURING DEVICES 



189 



in Fig. 108, which will be found to be very useful to drafts- 
men and others when very great accuracy in laying out 
wor^ is required. 




Fig. 110. 



This Protractor c?n be quickly set to any angle. It can 
be used either side up and on either of the two straight 
edges and it is of gTeat advantage in dividing a circle, 
transferring angles or laying off a given angle, without re- 
setting, on either side of a line. 

The Vernier reads to five minutes. 



190 



MACHINE SHOP PRACTICE 



It also forms a convenient extension to a T square and 
freqeuntly takes the place of 45° and 60° triangles. 

Two other styles of bevel protractors are shown in Figs. 
109 and 110. 





Fig. 112. 

Gauges, 

The gauge shown in Fig. Ill is for twist drills, from 
one-quarter to one-half an inch in diameter. Each size of 



MEASURING DEVICES 



191 



drill is designated by both vulgar or common fractions and 
also by decimal fractions. 

Fig. 112 illustrates a g'uage for Number Drills from No. 1 
to 60 inclusive. The size of each drill is given in decimal 



9e 



*e 



<b 



Q> 



& 






ft>: 



Uo^O 



cv> 





oi 



U.S. STANDARD GAUGE 

FOR SHEET AND PLATE 

RON AND SHEET 

N9 283 

Pig. 113. 

fractions. Gauges for sheet metal and plates, st r udai .1 
wire gauge and music or piano wire gauges, are sho n in 
Figs. 113, 114 and 115, respectively. 

Test Indicators. 

The dial test indicator shown in Fig. 116 is reliable, 
easily read and very sensitive. The slightest pressure upon 
the contact point produces a movement of the hand on the 
dial. The circumference of the dial is divided into 125 



192 



MACHINE SHOP PRACTICE 




Fig. 114. 

equal spaces, each one representing a movement of the con- 
tact point of one-half thousandth of an inch. One revolu- 
tion of the hand therefore indicates 1-16 inch, and two rev- 
olutions 1-8 inch, which is the capacity of the instrument. 

The dials are figured in two 
different ways. A is marked 
from to 62^, the figures de- 
noting thousandths, and is 
most useful in greater forward 
movement, measuring, index- 
ing, spacing, etc. B is marked 
from to 31^ to right and 
left, and is best for general 
use. By bringing contact 
point against the work with 
just enough pressure to give 
the hand one full turn, then seting it at 0, an oppor- 
tunity is given for one full revolution of the hand to both 
right and left of 0, showing a rise or drop in the work and 




Fig. 115. 



MEASURING DEVICES 



1<J3 




Fig. 116. 

the amount of variation. A most valuable feature is the 
adjustable dial. By turning the knurled rim the dial may 
be instantly moved to bring the mark to any point de- 
sired in relation to the hand. Each indicator is fitted with a 
friction joint and removable 3 inch rod, adapting- it for use 
in any position, at the top, bottom or side of the work, 
also with three hardened and ground contact points adapted 
for different classes of work. The special tool post and 
sleeve as shown above are useful in lathe work. For gen- 
eral work the indicator is adapted for use with a 9 inch or 
12 inch surface gauge. On lathe, planer, milling machine 
and in setting up machinery, this tool will be found very 
useful. Applications of the dial test indicator are shown 
in Fig. 117. 

The test indicator shown in Fig. 118 may be used to test 
and show the imperfections or truth of inside, outside or 
surface work. It can be instantly attached to the spindle 
or to the needle of any surface gauge and used in connee 



194 MACHINE SHOP PRACTICE 




MEASURING DEVICES 



195 




Fig. 118. 

tion with same to show the slightest variation in thou- 
sandths. A special holder, as shown in Fig. 118, is de- 
signed to go in the tool-post of a lathe, adapting it for use 
to show the accuracy of all kinds of lathe work, turning, 
chucking, or locating and centering work on a face plate. 
The head of the needle has three working points, equal dis- 
tance from its fulcrum, so the telltale needle will vibrate, 
reading in thousandths, when the work is in contact with 
either point— in front, above or below it. When in front, 
the spring operating the telltale needle needs to be re- 
versed to throw point of needle up instead of down as 
when used above or below the work. This may be instantly 
done by a slight turn of the disc to which the vibrating 
spring is attached. 

Speed Indicators. 

A form of speed indicator is shown in Fig. 119, which is 
used in connection with a watch to time the speed of shaft- 
ing or machinery. 

The instrument will register 5,000 revolutions. The large 
dial is graduated into one hundred lines, each one repre- 
senting a revolution of the spindle. The small dial has 
fifty lines cut upon its face, each representing one bun- 



196 



MACHINE SHOP PRACTICE 



dred revolutions of the spindle, or one complete turn of 
the large dial. A spring finger trip attached to the case 
engages with one of the lines in the small dial and holds 
it from revolving until the large dial makes one complete 
turn, when the trip pin passing under the spring trip lifts 




Fig. 119. 

it, and the dial is frictionally carried along by the large 
plate one line, thus showing that one hundred revolutions 
of the spindle have been made. The instrument has a 
hard rubber handle, making a safe insulator when used on 
electrical machinery. It is provided with rubber tips for 
both pointed and hollow centers. 

Fig. 120 is an attachment 
to be used in connection with 
a speed indicator of the form 
shown in Fig. 119, and speed 
is designed to show the num- 
ber of lineal feet per minute 
the periphery of a shaft or 
pulley is running and thus 
enable a workman to know if 
the speed is too fast, or is too 
slow to get the most work the 
tool will stand For instance, 
the speed of a cone pulley 
being turned needs to be 
changed at every step. Heretofore it has been all guess 
work as to the number of feet per minute the periphery 




Fig. 120. 



MEASURING DEVICES 



197 



of the work is traveling. It may be so fast as to 
heat and spoil the tool, or it may not be nearly fast enough 
to perform what should be done. The same is true when 
shifting the tool from the hub to the rim of a pulley. 
The rubber-banded indicator wheel may be instantly slipped 
on the spindle of the speed indicator, and when held 
against the periphery of a shaft or pulley a half minute 
or a minute, by dividing the figures showing the revolu- 
tions on the dial of the indicator by 2, the number of feet 
the surface of the thing is traveling is obtained, as each 
revolution of the indicator wheel shows six inches. Twice 
around is therefore equal to one foot. 




A tachometer or automatic speed indicator is shown in 
Fig. 121. This device indicates the speed of a shaft or 
any rotating body in revolutions per minute, without the 
aid of a watch. It will also automatically indicate any 
variation or fluctuation in the speed of the machine being 
tested. 

These instruments have been designed for the purpose 
of ascertaining at a glance the number of 'evolutions made 
by rotating shafts. Their construction is based upon fen- 



198 MACHINE SHOP PRACTICE 

trifugal force, and they consist of a case in which are 
mounted a pendulum ring, in connection with a fixed shaft, 
a sliding rod and an indicating movement. 

The apparatus is very sensitive and will indicate the 
slightest deviation in speed. 

Tachometers have been applied, with great success, to 
electric light engines, flour and cotton mills, and can be 
used to advantage on all machinery of which it is essential 
to know at all times, the exact speed at which it is moving. 



MACHINISTS' TOOLS 



m 





200 



A good workman will always have a good kit of tools, 
in which he will take pride. As a man is known by the 
company he keeps, so will a machinist be judged by the 
number and quality of the tools in his kit. A machinist 
who has a complete kit of tools, will not only get a job 
more readily but is liable to hold it longer than a me- 
"chanic who carries his outfit of tools in his pockets. 

In some large shops the workmen are furnished with a 
great many of the tools they use, on account of the special 
character of the work in hand, but in small or jobbing 
shops the machinist who has the best and largest kit of 
tools usually gets the best jobs. The tools illustrated here- 
with, are not shown as being a complete outfit, but are of 
sufficient variety to enable a mechanic to form some idea 
as to the class of tools necessary for general and even for 
some kinds of special work. 




1 1-1 ' ■ ^^i^rfS^ij'i'iiiftihfe 



Fig. 122. 

Bevel Protractor. The blade of the protractor shown in 
Fig. 122, closes in the stock either way against a stop, 
making a perfect square, plumb, and level. The turret is 
graduated on both sides, one in degrees, the other to show 

201 



202 MACHINE SHOP PRACTICE 

pitch to the foot, so that the blade may be set by the 
graduation for laying off: angles to any degree or any pitch, 
and the opposite branch of the stock will be right to lay 
out the complementary angle without mental calculation 
or error, for valley roofs, bridge work, stair gauges, etc. 
The levels are so arranged that work can be leveled up to 
any degree or pitch underneath or on top of a roof, rafter, 
stair stringer, etc. 

As a square or protractor with the sliding blade it can be 
used in places where a fixed blade could not and is a sub- 
stitute for a kit of squares from the shortest to the full 
length of blade, making a depth gauge for squaring in 
mortises and transferring measurements. It may be used 
in place of the carpenter's old time steel square with the 
advantage of being packed in a chest without taking up 
so much room. 

Without the blade the stock may be used in contracted 
places as a 6-inch level and plumb, while with an 18 or 
24-inch blade, a level and plumb of corresponding length 
is obtained. 




Fig. 123. 

Combination Bevel Protractor. Fig. 12S represents an 
inclinometer, try square* and bevel protractor combined. 

It is compact, convenient, and a complete substitute for 
several tools. 



MACHINISTS' TOOLS 203 

It consists of a stock and disc, both slotted to receive 
the blade, which folds in the stock. The blade attached 
to the graduated rotary disc may be secured at any angle 
from to 90 degrees, and by loosening the clamp screw 
it may be shortened or extended full length, or removed 
for a straight edge. 

The working face of the stock, extending both sides of 
the blade, admits of its being reversed, so that the same 
angle may be laid off in opposite directions without 
changing the angle in the tool, thus requiring but one-quar- 
ter of a graduated circle to obtain all angles both ways. 

At 90 degrees, the blade brings up against a casehard- 
ened screw, accurately adjusted, thus forming a try square. 
By holding the blade perpendicular, a plumb. By folding 
the tool, a level the full length of the blade. 




Fig. 124. 

Bevel. The advantages of the form of bevel, shown in 
Fig. 124, over other tools of this kind, consist in its having 
not only the blade slotted but the stock as well, thus admit- 
ting adjustments that cannot be obtained with an ordinary 
bevel. The clamping screw head is let into a rabbet, flush 
with the surface of the stock, which lies flat on the work. 

Spring Calipers. The calipers shown in Fig. 125 may be 
used with either plain or spring nut as shown. The view 
at the right in the cut shows a new inside transfer caliper 



204 



MACHINE SHOP PRACTICE 



with either a spring or solid nut. The bow is stiff, making 
the caliper reliable. After calipering the inside of a 
chambered cavity by springing in the legs they may be 
withdrawn, and as they spring back they will show the 
exact size of of the opening calipered. 




Pig. 125. 



Screw Thread Caliperes. Figures 126 and 127 show 
views of both outside and inside thread calipers with solid 
adjusting nuts. 

Keyhole Caliper. What is known as a keyhole caliper 
is illustrated in Fig. 128. This caliper may be put to a 
variety of uses and is an extremely handy tool. If the 
straight leg be ground off to a point it makes an excellent 
Hermaphrodite caliper. 

Firm Joint Caliper. The improvement in the calipers 
shown in Fig. 129 consists in the construction of the joint, 



MACHLVISTS' TOOLS 



205 




Fig. 126. 



Fig. 127. 



which is so made as to be drawn together by means of a 
screw. The main stud is squared and fitted to one leg, thus 
preventing the stud from turning when loosening and tight- 
ening, and insuring a smooth and uniform friction, of more 
or less tension to suit the user. 

Adjustable Firm Joint Calipers. The calipers shown in 
Fig. 130 can be instantly adjusted to their full extent, 
and as quickly locked firm in the joint, and yet provided 
with a sensitive adjustment. The improvement consists, 
first, in a socket joint made tapering, and locked or re- 
leased by a partial turn of the knurled disc drawing it 
together. A spring washer under the disc maintains an 
easy friction in the joint when unlocked. 

In the under side of the short arm is a slot containing 
a stiff spring. Riveted into the middle leg and projecting 



206 MACHINE SHOP PRACTICE 

through an opening in the arm, is a threaded stud on 
which is a knurled nut having a beveled hub, bearing 
against a cone in the arm, the action of the spring holding 

them together turns the nut, 
presses them apart and ad- 
justs the leg when the point is 
locked. As the spring takes 
up all backlash the legs are 
consequently firm. 

Caliper Rule. A caliper 
rule or scale is shown in Fig. 
131. It may be set to any 
desired measurement and 
locked in position by the but- 
ton shown in the drawing. 

Caliper Square. The tool 
shown in Fig. 132 has a 
double function — being grad- 
uated to read the circumfer- 
ence as well as the diameter 
of the article measured, the 
relation of circumference 
to diameter being shown 
by the graduations on upper 
Pig. iz8. corners of the rule. The rule 

is graduated in 32ds of an inch standard and 16ths of an 
inch circumference measure. All corners of the tool are 
rounded smooth to make it fit to carry in the pocket and 
agreeable to handle. The circumference measure will as- 
sist in calculating how many feet a minute the cutting 
tool in a lathe is doing on any diameter within the scope 
of the rule and so help to determine whether the tools 
should have a faster or slower speedo 

Rule. Multiply the circumference shown by the gauge 
by the speed the lathe runs per minute and the result will 




MACHINISTS' TOOLS 



207 




Fig. 129. 





Fig. 130. 



208 



MACHINE SHOP PRACTICE 



show the number of inches per minute the circumference 
is running and the tool consequently cutting. 








Fig. 132. 



Center Punch. The center punch shown in Fig. 133 is 
entirely new in design and combines features that make it 
much more convenient for laying out work to be machined 
or drilled than the ordinary center punch and hammer. 

The tool is of steel and is entirely self-contained, the 
striking mechanism being enclosed in the knurled handle, 
which is of such a size and form as to be held conven- 
iently in the hand. 

A downward pressure releases the striking block and 
makes the impression. The punch marks are of uniform 
depth and, therefore, easily and accurately followed. 



MACHINISTS' TOOLS 



209 




Pig. 133. 

The points can be taken out for grinding and are easily 
replaced if broken. 

Combination Square. With the adjustable scale the 
square shown in Fig. 134 forms one of the most son- 



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— to 


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— 


M ■= 




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^» 


~w 


w~^ 




E-/ 


"-11 




=> 


V-H 




E-d 


•w -== 




^"m 


SjI 




wm 


^jgj^^ui ^"ssgg^ ,« ^>^ Wj "^ \ 


\ §j|| 




- Li ....>.x 




^^1 


' '.= 


■ i— J3M 


CD 


o ■= 




Ei 


5^1 




~cp 


f-1 




=- --■ 


a — 




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ao -^ 






t^= 




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Sii 




Z^'f 


t» -= 




E 1 ^ 


K.H| 




t^jy 


(S_ -g; 





Fig. 134. 

venient and useful tools for mechanics' use. It is also a 
substitute for a set of common try squares, and is one of 
the best gauges made for transferring exact measurements 
or laying out work. It is convenien' for a depth gauge, 



210 



MACHINE SHOP PRACTICE 



or to square in a mortise, while with an auxiliary center 
head it forms a centering square, both inside and outside. 
Depth Gauge. The wire in the gauge illustrated in Fig. 
135 is held in a groove by a friction spring inside the nut 
while adjusting, and may be used close to the end, as well 
as in the middle of the straight edge. 




Pig. 136. 

By loosening the nut, the gauge may be neatly folded. 

Drill and Wire Gauges. A standard drill gauge is shown 
in Fig. 136 which will measure drills from one-sixteenth 
to three-eighths of an inch diameter. A standard wire 
gauge is illustrated in Fig. 137 which has a range from 
No. 5 to No. 36 wire. 



MACHINISTS' TOOLS 



21J 




Fig. 138. 



212 



MACHINE SHOP PRACTICE 



Dividers. Two forms of spring dividers are shown in 
Fig. 138, with solid adjusting nuts. A spring nut as 
shown in the drawing may be used instead of the solid 
nuts. One of the spring dividers is fitted with a small 
handle or twirler. 

Hammers. A machinist's hammer with 
straight and ball-pens is illustrated in Fig. 
139. This is the form of hammer most 
generaly used by machinists for all round 
work. 

Key Seat Rule. The device shown in 
Fig. 140 is designed to transform an.7 
common steel scale into a key set rule. 

They can be put on or off almost in- 
stantly, and are a complete substitute for 
Fig. 139. a more costly tool. 

They may be used with a combination square blade, or 
with any straight rule, with accurate results. 





Fig. 140. 

Hand Vises. Two forms of hand vises are shown in 
Fig. 141. These are very useful tools for holding small 
work. The vise shown in the upper view is fitted with a 
handle, while the one in the lower view is intended to be 
held in a bench vise. 

Levels. The level shown in Fig. 142 is so constructed 



MACHINISTS' TOOLS 



213 



that it can be accurately adjusted, and when so adjusted 
is not liable to get out of truth, the vial being set in tubes 
having solid ends which 
are firmly clamped to 
the base. The outer 
tube may be turned so 
as to protect the glass 
when not in use. 

In lining up shafting 
or erecting machinery a 
level is absolutely in- 
dispensible. 

Micrometers. A small 
micrometer reading to 
thousandths of an inch, 
as shown in Fig. 143, 
should be a part of every 
machinist's kit as its 
uses are many and Fig. 141, 

varied, more especially on small work. 

Pliers. In the cutting-plier illustrated in Fig. 144, the 
jaws are detachable, so that they can be removed, ground, 
and adjusted when they have become worn. Each jaw can 






Fig. 142. 



be ground away to the extent of one-quarter of an inch, 
remaining as good as new for practical use. and when used 
up new jaws can be procured. 

A screw through the jaw engages with a spline in the 



214 



MACHINE SHOP PRACTICE 




Fig. 143. 



frame and draws the jaw firmly down to the toothed seat, 
holding it securely. 

Another feature in this cutting-plier is a flat spring be- 
low the cutting edges and over the joint, forming a yield- 
ing seat for the end of the wire to press against while 
being cut. This obviates the danger of breaking the jaws, 
as often happens with other styles of pliers which allow 
the wire to be inserted against a solid surface. 




Fig. 144. 

A pair of flat pliers or nippers are shown in Fig. 145, 
which may be put to a great many uses, especially when 
assembling small work. 

Plumb-bob. A plumb-bob such as shown in Fig. 146 will 
be found to be an invaluable adjunct to a kit of tools. In 



MACHINISTS' TOOLS 



215 





Fig. 146. 



Fig. 145. 

lining up shafting 
from one floor to an- 
other and sometimes 
in erecting machin- 
inery its use will be 
found to be almost 
indispensable. 

Surface Gauge. 

The gauge illus- 
trated in Fig. 147 has 
in addition to the V- 
shaped groove in the 
end, a corresponding 
groove in the bottom 
adapting the gauge 
for use in cylinder- 
ical work. It is also 
provided with two 
gauge pins in the 
rear end of the base 
that can be pushed | 
down and used 
against the edge of 
the plate or the side 
of the T slot. Fi s- 147 - 

The post swivel can be set and rigidly clamped 
in any position from the vertical to the hori- 
zontal, and the scriber used below the base 
as a depth gauge. 




216 



MACHINE SHOP PRACTICE 



The scriber has a fine adjustment that can be used after 
the sliding block is set at the approximate height. This 
device is simple and cannot get out of order. The ad- 
justment is made by means of the large knurled nut, shown 
in the drawing, which, when turned, revolves the scriber 
clasp slowly and continuously, and allows the scriber to be 
set at any position within its range. 




Fig. 148. 

Screw Drivers. Figure 148 shows a pocket screw driver 
and brad awl made in one piece, this being telescoped 
within the handle when not in use. The shape of the han- 
dle enables it to be used as an emergency wrench, which 
is often of the greatest convenience. 

It takes the place of a number of tools usually carried 
in a kit. 




Fig. 149. 

The screw driver shown in Fig. 149 has a knurled hard- 
wood handle, large enough to fill the hand and give lev- 
erage. Its steel shank has a socketed end to which" is 
fitted a set of three screw driver tips of different sizes, 
adapted for screw heads from very small up to three- 



MACHINISTS' TOOLS 



217 



eighths of an inch. Either size may be instantly with- 
drawn and another inserted, thus supplying a full set of 
screw drivers at a fraction of the cost of others requiring 
as many handles as drivers. The tips are shaped and tem- 
pered so as to give the greatest strength. 




Fig. 150. 

A plain wood handle screw driver is shown in Fig. 150. 
This is a very useful bench tool. 

Screw-Pitch Gauges. The gauge shown in Fig. 151 has 
the following pitches: 4, 4y 2 , 5, 5y 2 , 6, 7, 8, 9, 10, 11, 
liy 2 , 12, 13, 14, 15, 16, 18, 20, 22, 24, 26, 27, 28, 30. The 




Fig. 151. 

teeth are sharp and clean cut, and it can be used inside 
of a nut as well as on the outside of a screw or bolt. It 
is also a convenient and reliable tool to use as a 60-de- 
gree center gauge and gauge to test the grinding of either 
an inside or outside threading tool. 

Steel Scales or Rules. Figure 152 illustrates a machin- 
ist's pocket scale or rule. These are made in different 



218 



MACHINE SHOP PRACTICE 



lengths and thickness, and may be had graduated in inches 
or in millimeters. 



Iff - 




I'l'i'pi'l'I'lTi 1 



kUilUllUIIUi 



Fig. 153. 

Standard Square. In the square 
shown in Fig. 153 the blade is not 
rivited or soldered to the stock, but 
is firmly held by a bolt and nut, 
by means of which the tool can be 
readily taken apart, and when worn 
the blade and stock can be reground 
or lapped, and put together again as 
as new. 

Thread-Gauge. The gauge illustrated in Fig. 
154 is used for setting screw-cutting tools and 
testing lathe-centers. 




good 




Fig. 154. 

Tram-points. The tram-points shown in Fig. 
155 are made of bronze metal, with forged and 
hardened steel points. 

Either point can be removed, and the pencil 
.j -._ socket accompanying each pair put in its place< 

The tram-points are adjustable like spring dividers. 
Try Square. The square shown in Fig. 156 has concave 
depressions in each side of the stock, which not only re- 
duce its weight but make it more convenient to hold b«- 



MACHINISTS' TOOLS 



219 




Fig. 155 

tween the thumb and finger 
while being used. The stock 
is casehardened and the 
blade hardened to a spring 
temper. Fig - 156 ' 

Wrenches. In jobbing shops and on repair work a mon- 
key-wrench is a very necessary tool, but in large factories 




Fig. 157. 

who manufacture specialties sets of standard spanner 
wrenches are provided for each workman. A standard 
type of monkey-wrench is illustrated in Fig. 157. 



SHOP TOOLS 



221 



Angular Bit-Stock. The universal angular bit-stock 
shown in Fig. 158 is to be used in connection with a brace 
and bit for boring holes in places where the brace and bit 
alone could not be used. It can be varied in any position 




Fig. 158. 

from a straight line parallel with the brace chuck to the 
angle shown in the cut. The ability to vary the angles, 
either at the commencement or during the operation of 
boring a hole, is an important feature of this tool. 

Arbors. Mandrils or arbors should have their centers 
so formed as to leave a recess or counterbore about the 
countersink in their ends, the object being to prevent the 
blows given to drive the mandril into the work from in- 

223 



224 MACHINE SHOP PRACTICE 

juring the centers and thereby causing the work to run 
out of true. 

Belt Clamp. The belt clamp shown in Fig. 159 has 
corrugated and beveled jaws which insures a strong grip 
to belting. 

The frame is made of Rock Maple, and the screws of 
the best wrought iron with square head and quick pitch. 

These clamps are used for tightening and putting to- 
gether large belts, and is one of the best clamps made, 
combining strength, simplicity and convenience. No shop 
should be without them, as once taking up a belt will fre- 
quently save its cost. 




Fig. 159. 

All the clamps are made with iron screws. They are 
rapid working and durable. 

Belt and Lace Cutters. These are an indispensable arti- 
cle in the shop. Fig. 160 shows two forms of such tools. 

Bench Shears. The shear illustrated in Fig. 161 has the 
capacity of cutting any length or width, and 3-16 inch in 
thickness. A prominent feature is in the adjustment of 
the shear arm by means of an eccentric at the back. With 
this arrangement a greater or less degree of angle can be 
quickly given to the blades, so that in cutting thin stock 
it will not curl the metal. The length of the blades used 
are three inches. It has a gauge on the table for cutting 
angles, and one on the arm for gauging the width to be 
cut, with the standard divisions marked on the bar. Also 
a clamp for holding down the metal. 



SHOP TOOLS 



225 





Fig. 160. 




Fig. 161. 



226 



MACHINE SHOP PRACTICE 



Blacksmith's Drill. This machine, shown in Fig. 162, 
is designed for carriage makers and heavier blacksmith 
work. It is built heavy and has a large capacity. 

It will drill a 1%-inch hole to 
the center of a 16-inch circle, 
4% inches deep. 

The greatest distance from the 
spindle to the table is 22 inches. 
The drill-socket screws on to 
the spindle, and takes a drill 
with 41-64 inch round shank. 
It can be removed and a Uni- 
versal Chuck put on in its place. 

The drill has an automatic 
feed, a swing-table 11 inches in 
diameter, and grinding attach- 
ment. 

The drill has two speeds which 
are obtained without changing 
the crank. This gives high 
speed on the balance wheel all 
the time. The change is made 
in an instant by turning the 
small lever to the right or left. 
Blacksmith's Forge. The 
forge illustrated in Fig. 163 is 
an ingenious invention as re- 
gards the three-piece construc- 
tion for producing a regular 
and continuous positive blast 
with great ease. The forge is constructed from struc- 
tural steel, making it strong, stiff and light. The ma- 
chinery is all inclosed in an oil-tight casing, and entirely 
noiseless. It has no belts or friction. It is fitted through- 
out with ball bearings. It can be taken apart for trans- 




Fig. 162. 



SHOP TOOLS 



227 




Fig. 163. 

portation and again set up for use in several moments. 
The forge is adapted for government use, elevated and 
steam railroads, bridge and tank builders, miners and pros- 
pectors, boiler repairers, or any portable work requiring 



228 MACHINE SHOP PRACTICE . 

compactness and lightness, with a strong blast. If neces- 
sary, it will produce a blast to weld 3y 2 to 4-inch iron in 
ten minutes. The crank to produce the blast can be turned 
either way. 

Blacksmith's Tools. The effect of blows delivered upon 
forged work by the blacksmith's tools is not only greater 
upon the exterior than upon the interior of the metal, but 
is greatest upon that part of the forging which receives 
the most working, and upon that part which is at the 
lowest temperature during the finishing process: because 
the blows delivered during the finishing process are lighter 
than those during the earlier stages of the forging, and 
hence their effects do not penetrate so deeply into the 
body of the metal. Then again, on that part of the metal 
which is coolest, the effects of the light hammering do not 
penetrate so deeply; and from these combined causes, the 



Fig. 164. 

tension is not equally distributed over the whole surface 
»f the forging, and hence its removal, by cutting away the 
outer surface of any one part, and thus releasing the ten- 
sion of that part, alters the form of the whole body, which 
'Joes not, therefore, assume its normal shape until the outer 
skip, of its whole surface has been removed. 
3*«*ASt Drills. The drill shown in Fig. 164 has ball bear- 



SHOP TOOLS 229 

ings, nickel plated stock and chuck, cocobola handles, ex- 
tension crank, alligator jaws, which hold both round and 
square shanks, and a level attachment to enable the op- 




w -r« R Fig - 166 - 

Fig. 165. 

erator to see when the tool is held true. The gears are 
cut and are changeable from 1 to 1 to 3 to 1. 

The breast drill illustrated in Fig. 165 has all the ad- 
vantages of the one shown in Fig. 166, and in addition 



23C 



MACHINE SHOP PRACTICE 



has a wide rimmed gear to be grasped between the thumb 
and fingers when the drill is used for delicate work. In 
this manner it can be run without liability of breaking 
the drill points. It is double-geared and IIV2 inches in 
length. 

Breast Drill Attachment. The drill shown in Fig. 166 
is designed to apply to a breast drill, so as to convert it 
into a drill press or bench drill. The illustration shows 
i\ breast drill thus converted. 

The bench clamp, vise rest and frame are all clamped 
to the main standard, and can be moved up and down, or 
swung to the right or left, and by means of the thumb 
screws provided, clamped or secured at any desired point. 

The vise is hung on a pin which is off the center, so as 
to give the operator the advantage of a /ariety of posi- 
tions 




Fig. 167. 

The operator may, if desirable, work below the bench by 
dropping the frame and fixtures down on the standard, 
and securing the upper end of the same in the bench 
ilamp. This is very convenient in bicycle repairing. The 



SHOP TOOLS 231 

number of positions, heights and adjustments that will 
suggest themselves as necessity demands, with this tool, is 
numberless. 

Fig. 167 shows the breast drill designed for use with this 
attachment. 

Center Drill and Countersink. Fig. 168 represents a 
combined drill and countersink for center drilling, the drill 
and countersink being in one piece. When very true Work 
is required it is preferable to so shape the countersink 
that the lathe center will first bear at the smallest part 
of the cone. This will cause the countersink to wear and 
keep true with the hole. 




Pig. 168. 

If the center drilling is to be done by hand it is very 
important to relax every few seconds the hold upon the 
work sufficiently to permit it to make about a third of a 
revolution, which may be done while the other hand is 
supplying oil to the drill. The object and effect of this is 
to cause the center drilling to be true, which otherwise it 
would not be, especially if the work is comparatively 
heavy, or heavier on one side than on another. 

Chucks. Fig. 169 shows a new form of lathe chuck, in 
which the jaws are operated by a rack and a key pinion. 

This construction has many advantages over the old 
style, in that the jaws are stronger and move in that part 
of the chuck which is attached to the driving spindle. 
Great firmness is gained to the chuck by this arrangement. 
The threaded and working parts are covered and thereby 
secured from injury or dirt. 

The chuck shown in Fig. 170 has projecting jaws and 
the combination prevents larger work than the chuct is 



232 



MACHINE SHOP PRACTICE 




Fig. 169. 



SHOP TOOLS 



233 




Pig. 171. 
designed for being used. It is very powerful and guaran- 
teed to hold true and not injure the shank of the drills. 
It holds round and square work. The jaws are guided by 



234 MACHINE SHOP PRACTICE 

three strong gibs, and the screws are larger than in any 
chuck of this description. The jaws and screws are made 
from cast steel. 

Fig. 171 represents a form of chuck, which may be used 
as an independent or as a universal chuck. Each of the 
screws for operating the jaws is provided with a bevel 
pinion, and behind these pinions is a ring provided with 
teeth, and which may be caused to engage with or disen- 
gage from the pinions as follows: The width of the rack 
has a beveled step, the outer being thicker than the inner 
diameter. Between this ring or rack and the face of the 
chuck is placed, beneath each jaw, a cam block beveled 
to correspond with the beveled edge of the circular step. 

Each cam block stem passes through radial slots in the 
face of the chuck, so that it may be moved towards or 
away from the center of the chuck. When it is moved in, 
its cam-head passes into the recess or thin part of the cir- 
cular rack which then falls back out of gear with the jaw- 
screw pinion. But when it is moved outward the cam- 
head slides under the circular rack and places it in gear 
with the jaw-screw pinion. To change the chuck from an 
independent one to a universal one, all that is necessary 
to do is to push the heads of the cam-blocks outwards. 

Clamps. Steel clamps for holding work on drill-press 
tables or surface plates are a very handy tool in a shop. 
Eig. 172 illustrates a form of clamp much used for this 
purpose. 

Cold Chisels. Chisels are made from two shapes of bar 
steel, one of which is octagonal, and the other of flat- 
oval section. With the latter shape the cutting edge and 
the flat are parallel, and the broad flat is the best guide 
in holding the chisel level with the surface to be chipped. 
Either of these chisels is of a proper width for wrought- 
iron or steel, because chisels used on these metals take all 
the power to drive that can be given with a hammer of 
the usual proportions for heavy chipping, which is: Weight 



SHOP TOOLS 



2& 




Fig. 172. 

of hammer 1% pounds, length of hammer handle 15 inches, 
the handle to be held at its end and swung back about 
vertically over the shoulder. If so narrow a chisel be used 
on cast-iron or brass and given full-force hammer-blows, 
it will break out the metal instead of cutting it and the 
break may come below the proper depth and leave ugly 
cavities. For these metals the chisel should be made 
wider so that the force of the blow will be spread over a 
greater length of chisel edge and will not move forward 
so much at each blow, and therefore it will not break the 
metal out. Another advantage is, that the broader the 
chisel the easier it is to hold its edge fair with the work 
surface, and make smooth chipping. 






Fig. 173. 

Counterbores. Pin drills or counterbores are used to 
drill the recess for the heads of machine screws. An illus~ 
tration of a counterbore is shown in Fig. 173. 



536 



MACHINE SHOP PRACTICE 



Fig. 174. 



Depth Gauge. Fig. 
174 shows the head 
of the depth gauge 
together with a por- 
tion of the barrel and 
rod. It will measure 
to 3 inches in depth. 

The base is about 
7-16 inch wide and 
the rod about 1-8 
inch in diameter. 

A spiral spring in 
the barrel forces the 
rod against the bot- 
tom of the hole or 
recess to be measured 
and by use of the 
clamp screw the rod 
is securely locked in 
position. 

Dies. Dies are 
usually cut of a 
larger diameter than 
the size of the bolt 
the dies are intended 
to cut. This being 
done to cause the 
dies to cut at the cut- 
ting edges of the 
teeth which are at or 
near the center of 
each die, so that the 
threads on each side 
of each die may act 



as guides to steady the dies, and prevent them from wabbling 
as they otherwise would do. The result of this is, that the 




SEOP TOOLS 



237 



angle in the thread in the dies is not the correct angle for 
the thread of the bolt, even when the dies a v « the closest 
together, although the dies are nearer the correct angle 
when in that position than in any other. A very little prac- 
tice at cutting threads with stocks and d!es will demon- 
strate that the tops of the threads cut on a bolt are larger 
than the diameter of the bolt, before the thread was com- 
menced to be cut, which arises from the pressure, placed 
on the sides of the thread of the bolt, by the sides of the 
thread on the dies, in consequence of the difference in 
their angles. Which pressure compresses the sides of the 
bolt thread and causes a corresponding increase in its 
diameter. It is in consequence of the variation of angle 
in adjustable dies that a square thread cannot be cut by 
them, and that they will not cut a good V thread. 



Fig. 175. 



Drills and Drill-holders. Twist drills, as shown in Fig. 
175, are generally used in machine shops, and vary in size 
according to the nature of the work. In ordinary shop 
practice from three-eighths of an inch to V/ 2 inches in 
diameter is the range of holes drilled. Therefore, the drills 
are made in sets, and with each set is a steel socket which 
fits the drill-press spindle at one end, and at the other end 
the recess fits all the drills in the set. They are, there- 
fore, interchangeable. 



238 



MACHINE SHOP PRACTICE 



Drill sockets are shown in the illustration in Fig. 176. 

To enable the drill to be easily extracted from the 
socket, the latter is provided with a slot, as shown in the 
figure; this slot passes entirely through it. The drill end 
protrudes into the slot, so that if a key or wedge be driven 
into the opening the drill will be forced out. 





Fig. 176. 



Drill Grinders. For the accurate grinding of twist drills, 
the grinders shown in Fig. 177 will be found to be very 
suitable for the average machine shop. 

Emery-wheel Dressing Tools. For the purpose of re- 
moving the glazed surface from emery-wheels, dressing 
tools are used as shown in Fig. 178. These consist of ser- 
rated or grooved disks, which are pressed against the face 
of the emery-wheel, and moved back and forth across it. 

Gauges. The gauge shown in Fig. 179 furnishes the cor- 
rect form for tools used in turning the threads of worms, 
when the worm wheels are cut with involute cutters. The 
figures on the gauge correspond to the number of threads 
per inch of the worm. 

The screw pitch gauge shown in Fig. 180 will measure 
the threads of nuts as well as of screws and contains the 
pitches 9, 10, 11, liy 2 , 12, 13, 14, 15, 16, 18, 20 on one 



SHOP TOOLS 



239 




240 



MACHINE SHOP PRACTICE 





Fig. 178. 





Fig. 179. 




Fig. 180. 



SHOP TOOLS 



241 



end and 22, 24, 26, 27, 28, 30, 32, 34, 36, 38 and 40 on the 
other end. 

The arrangement of blades hinged on each end of the 
case enables any desired number to be quickly placed in 
position for use. 

There are 22 pitches, including pipe thread pitches, ll 1 /^ 
and 27. The 8 pitch may be determined by using the 16 
pitch blade. 

The 11 smaller pitches are on blades made narrower than 
the 11 larger ones, so that they have a wider range of use 
in measuring the threads of nuts than would be the case 
were they all of one size. 

The gauge numbers are stamped on Hie outside of the 
frame, as well as on both sides of each blade, allowing the 
user to determine the position of a desired number at a 
glance. 





Fig. 181. 

Hack Saws. These frames, the frames of the saws shown 
in Fig. 181, are all made of steel, and as seen in the cut 
are adjustable so as to face the blade in four different di- 
rections. The extension frames will hold different lengths 
of blades. The solid frames only hold the 8 inch blades, 



242 MACHINE SHOP PRACTICE 

this being the length most in use. They all have staple 
shaped pins to hold* the blades in the frame which are so 
arranged that they cannot fall out. 

Lathe Dogs. Figures 182 and 183 show the ordinary 
form of lathe-dog or driver, with set-screws to secure them 
to the work. A screw-clamp lathe dog is illustrated in Fig 1 . 
184 which has half-round grooves in the upper and lower 
clamping pieces so as to hold the work without marring 
the surface or injuring it in any manner. 





Pig. 182. Fig. 183. 

Lathe Threading Tool. A new form of lathe threading tool 
is shown in Fig. 185. 

Levels. The level shown in Fig. 186 has, in addition to 
the regular parallel vial, a cross level which enables one to 
place or hold the base on a shaft level in its cross section, 
not canted sidewise, for the shape of a level glass is such 
that, though true as adjusted on a flat surface, it will not 



SHOP TOOLS 



243 




Fig. 184. 




Fig. 185. 




Fig. 186. 



be reliable when canted sidewise. Hence the value of the 
cross level, not only to test the truth of shafting, but other 
surfaces which tend to throw the level into a slanting posi- 
tion. 



244 



MACHINE SHOP PRACTICE 



The base of this level has an improved concaves ^piowtf 
running through the length of its base, leaving a flat mar- 
gin each side, which also improves its seat for flat work, 
while forming an absolutely true and reliable seat for 
shafting, and is better than a V groove. 

Micrometer. The micrometer shown in Fig. 187 meas- 
ures all sizes less than one inch by thousandths of an inch. 
The outer end of the frame is the same size as the meas- 
uring spindle, and, as the edges of the measuring surfaces 
are not beveled, but left square, it is convenient for gaug- 
ing under a shoulder, or measuring a small projection on a 
plane surface. 




Fig. 187. 



The adjustment of the measuring screw is made by ar 
adjustable threaded nut which produces the necessary fric 
tion by binding the thread evenly on the angle, thus ob- 
viating the use of slots, the points of which are apt to 
rough the thread if improperly clamped. 

Every micrometer is provided with a clamp nut, which 
clamps the spindle and preserves the setting. 



SHOP TOOLS 



245 



A micrometer sheet metal gauge is shown in Fig. 188. 

This gauge has a 2 inch depth of throat to reach over 
the edge of the sheet metal to gauge its thickness nearer 
the center. It has one-half an inch movement of the 
screw. The screw is covered by a shell with its indicator 
mark, which enables one to take up wear to a nicety and 
insures a correct reading, the anvil remaining solid. It 
also has a ratchet friction feed, which insures uniform 
pressure against the work without springing the frame, as 
well as a lock nut to lock the spindle firm when desired to 
make a solid gauge. 




Pig. 189. 

Planer Jacks. This jack is very useful article for rais- 
)ng and levelling heavy castings on a planer. An illustra- 
tion of the jack is shown in Fig. 189. 



246 



MACHINE SHOP PRACTICE 




Fig. 190. 

Power Hack Saw. The machine illustrated in Fig. 190 
is designed for cutting brass, iron and steel. It will cut 
any size up to 4y 2 inches in diameter, and any shape that 
can be held in the vise. Great speed is not claimed in cut- 
ting, but metal can be cut more rapidly in this machine 
than in a lathe or planer, or heating and cutting by a 
blacksmith. By its use a good percentage of metal is saved, 
as the pieces cut are left smooth, and no labor or metal 
is lost in squaring up. This saving in high-priced steel is 
quite an item in stock to say nothing of the labor. The. 
blades used are Star hack saws, 10, 11 or 12 inches in 
length. The machine should run from 40 to 45 revolutions 
per minute. 



SHOP TOOLS 



247 



Taps. Machinists' hand taps are made in three styles: 
Taper, Ping and Bottoming Taps, as shown in Fig. 191. 










Fig. 191. 

Taps for use in holes to be tapped deeply should be of 
slightly larger diameter than those used to tap shallow 
ones, because in deep holes the tap is held steady by its 
depth in the hole, and whatever variation there may be 
in the pitch of the threads in the hole and those on the 
bolt, is experienced to an extent as much greater as the 
length of the thread increases. 




Fig. 192. 




193. 



A short Hob or master tap is illustrated in Fig. 192 and 
a Machine or Nut Tap in Fig. 193. 

Vises. The vise shown in Fig. 194 is designed for jewel- 
ers, tool makers, and machinists ' use. All parts are drop- 



248 



MACHINE SHOP PRACTICE 




Fig. 194. 

forged of best steel for the purpose. The jaws have a 
positive opening and closing movement in parallel lines, 
actuated by a right and left hand screw, moving the jaws 
simultaneously towards or from each other. A hole is en- 
tirely through the handle and the jaws will grasp and hold 
central, round wire from one-sixteenth of an inch up to 
and including one-quarter of an inch in diameter. The 
jaws open three-quarters of an inch. 



SHOP TOOLS 



249 




Fig. 195. 




Fig. 196. 

Several forms of standard plain and swivel vises are 



shown in Figs. 195 to 199. 



250 



MACHINE SHOP PRACTICE 




Pig. 197. 




F;s- 193. 



A drilling attachment which may be adapted to use with 
4imost any ordinary vise is shown in Fig. 200. 

A quick opening form of pawl and ratchet vise is shown 
\n Fig. 201. It also has a swivel base. 



SHOP TOOLS 



251 




Pig. 199. 

Wrenches. For shops engaged in the manufacture of 
standard or duplicate work, a set of wrenches as shown 
in Fig. 202 is an almost indispensable necessity. These are 




Fig. 200. 

made in all sizes from ^ of an inch to l 1 /^ inches, and in 
the styles shown in the drawing. 



252 MACHINE SHOP PRACTICE 




Fig. 202. 




I 



254 



Erecting Machine Tools. When machine tools are first 
received, if they have been shipped any distance in an open 
or box car, a large amount of dirt and grit will have ac- 
cumulated in transit. In order to thoroughly remove these, 
the tools should be taken carefully apart and thoroughly 
cleaned. 

The next thing to be considered is the foundation, and 
if on the ground floor, when possible, so that the tools be 
placed on a stone foundation. The advantages obtained 
by so doing will well repay the extra cost. Careful level- 
ing of the machine after it has been placed in position is 
inoperative. Be sure the level is accurate and sensitive, 
and in addition to this always use a true straight edge. 
With these the machine can be tested until known to be 
correct. 

The countershaft should also be level, and in strict align- 
ment with the main line. 

One of the most important things in starting a new ma- 
chine, and the one which is most often neglected, is to see 
that the machine is well lubricated, and with a good qual- 
ity of oil. The very best oil is the cheapest, and should be 
used in generous quantities, particularly for the first few 
weeks the machine is running. Convenient places are pro- 
vided for oiling all bearings, and careful attention should 
be given to see that all bearings and sliding surfaces are 
well lubricated. 

If these directions are carefully followed there will be 
little trouble about the machine running properly. 

Bolt Cutters. 

Bolt-Cutting Machines or Bolt Cutters are employed to 
cut the threads upon bolts. These machines are made 

255 



256 



MACHINE SHOP PRACTICE 



both single and double, that is, with a single or a double 
head. Each head contains dies, which are provided with 
means to close them to cut the thread to the required 
diameter, and in the cases of simple machines to run 
backward to withdraw the dies from the bolt, while in 
the more improved machines the dies are opened auto- 
matically so that the bolt can be withdrawn as soon as the 
thread is cut upon it. The bolts are held in jaws or chucks 
that are moved by hand-wheels operating right- and left- 
hand screws so that the jaws open and close equally, and 
the bolts will be held in line with the thread-cutting dies. 
The bolts are usually moved up to the dies by levers and 
sometimes by a rack and pinion motion. 




Pig. 203. 

Bolt-Cutter Head. The head shown in Fig. 203 is spe- 
cially designed to receive detachable dies, to hold them 



MACHINE TOOLS 267 

rigidly at any desired diameter, and to open or draw dies 
away from the thread when the cutting is completed. In 
addition to the time saved, which is practically equal to 
the time of cutting, the quality of the work performed is 
fully equal to that cut in the lathe. The barrel or die 
holder is coupled to the main spindle of the machine, at its 
outer end are four slots through which the dies are moved 
to and from its axis. These dies are plain flat pieces of 
steel, held in a die case, at the upper end of the case is 
a large cj'lindrical head, which receives all the outward 
thrusts of the dies. Special attention is drawn to this con- 
struction, which is far superior to any tongue or groove 
form. The adjustment of the dies is secured by stopping 
the travel of die ring at different points on the inclined 
head of the die cases. 

Bolt-Cutter. The lead screw in the machine illustrated 
in Fig. 204 is located directly beneath the head stock and 
carriage, and is driven by direct gearing from the main 
spindle. It is of ample size and with a sufficiently coarse 
thread to insure long life, and need never be removed from 
the machine in order to change for the pitch of thread to 
be cut. Change gears to cut the standard pitches within 
the capacity of the machine are provided. The lead screw 
is engaged by a split nut, contained within the carriage. 
This nut is operated by a hand lever conveniently placed. 
An automatic safety device, which should be used as such 
only, disengages the nut from the lead screw at the end 
of the forward travel of the carriage and prevents any 
injury to the machine which would result if, through care- 
lessness of the operator, the lead screw were allowed to 
force the carriage against the die head. This attachment 
automatically opens and closes the die head by the forward 
and backward travel of the carriage, and can be adjusted 
so as to operate for any length of thread to be cut on 
bolts of any length within the capacity of the machine. 



258 



MACHINE SHOP PRACTICE 




MACHINE TOOLS 



259 



The vise jaws are opened and closed by means of a right 
and left hand screw, which on the smaller sizes of the 
single and double head machines is operated by a hand 
wheel directly. On the larger sizes the screw is operated 
by the hand wheel through reduction gears. The vise 
screws of triple and quadruple machines are operated by 
adjustable levers. The carriages of the single and double 
head bolt cutters are operated by a pilot wheel and rack 
and pinion. The rack pinion of the larger machines is 
operated through reduction gears. All gears are cut from 
the solid metal and provided with covers to prevent injury 
to them and to the operator. 




Fig. 205. 

One ajid One-half Inch Motor-Driven Bolt Cutter. The 

illustration in Fig. 205 shows the rear view of a l^-inch 
gear connected single motor-driven bolt cutter. The motor 
is of the direct current, variable speed, reversible type, 



260 MACHINE SHOP PRACTICE 

bolted vertically to the rear side of the machine column, 
where it is free from oil and chips. A train of gears trans- 
mits the power from the motor to the main spindle of the 
machine. 

This arrangement gives, with the field control only, nine 
spindle speeds, for cutting either right or left hand, vary- 
ing from 33 to 66 revolutions per minute. 

Three-inch Motor-Driven Bolt Cutter. The design of the 
machine shown in Fig. 206 embodies several new and im- 
proved features. The main spindle is driven by a gear 
midway between the bearings, and all gearing is placed on 
the back side of the machine, instead of projecting from 
the end. The locking bolt and hand lever of the back gears 
are rendered more accessible. All the gears are covered. 

A direct current, variable speed, reversible motor gives, 
with field control only, in connection with the back gearing, 
18 separate spindle speeds, varying from 6 to 75 r. p. m. 

Boring Machines. 

Figure 207 illustrates a vertical boring-mill in which 
the horizontal table A is driven by means of bevel-gears. 
The bed is cast in one piece and well ribbed and braced. 
The housings B are of hollow section and have wide flanges 
where they are connected with the bed, to which they are 
attached by means of bolts passing through seamed holes. 
The cross-rail C is of box-girder form and has a wide slide 
surface for the saddles D. The saddles are made right 
and left so as to allow the tool-bars E to come close to- 
gether. The tool-holders F are made from solid steel 
forgings and are held in the tool-bars by steel keys. The 
tool-bars are held in adjustable capped bearings and may 
be swung to angle, being counter weighted by weights at- 
tached to the chain shown at G. Power-feed screws H are 
used for elevating the cross rail. The tool-bars E are 
adjusted vertically by means of the hand-wheels K and 



MACHINE TOOLS 



261 




262 



MACHINE SHOP PRACTICE 




Fig. 207. 



have a transverse or cross movement through the shaft L. 
The tool-holders F will grip the tools in any position, and 
are easily removable for the insertion of cutter-bars or 
special tools. The counterweight acts at all angles through 
the wide bearing surface and in addition, the table has an 
annular, angular bearing which increases the bearing sur- 
face and gives steadiness of motion. It has also a self- 
centering tendency, so that the combined weight of the 
table and spindle, as well as that of the work upon the 
table, tends to preserve and not destroy the alignment. 



MACHINE TOOLS 263 

The advantages in the boring mill are that the work lies 
upon a horizontal table, and the weight of the table and 
the work is distributed on a large bearing provided for that 
purpose, which gives rigidity and smooth-cutting qualities, 
thereby avoiding all jar or trembling, which usually occur 
in overhung lathes. 

Cylinder Boring Machine. A cylinder-boring machine is 
shown in Fig. 208, which is suitable for boring small pump, 
steam and gas engine C3 7 linders. 

The boring bar is provided with four power feeds, which 
are changed from one to another by means of a sliding 
key. It also has a quick and a slow hand motion, and is 
fitted with ball thrust-bearings. 

A long bar running clear through the tail bearing can be 
furnished, or a short one with a taper hole in the end 
for the use of smaller bars. A simple form of facing head 
is readily attached to the boring bar. 

The drive is accomplished from a single pulley by means 
of a variable speed transmission, which gives any speed 
from 10 to 50 revolutions per minute. 

This machine was designed to do a large variety of accu- 
rate boring and drilling, such as is done in machine tool 
shops or in the tool rooms of manufacturing establish- 
ments. 

It has been built with special view to accuracy and per- 
manence of alignment, and is accurately fitted to surface 
plates and straight-edges and carefully lined up, to be true 
throughout the range of its various adjustments. 

Automobile manufacturers will find them especially ap- 
plicable to their work in boring cylinders, milling facets, 
drilling frames, etc. 

Horizontal Boring Machine. This machine shown in Fig. 
209 is designed for all kinds of boring, drilling and milling, 
for the latter it is particularly valuable, doing work that 
ordinarily would require a large planer. 



264 



MACHINE SHOP PRACTICE 




MACHINE TOOLS 



265 




266 MACHINE SHOP PRACTICE 

The spindle is steel, 5 inches in diameter and powerfully 
geared, giving 10 changes of speed and can be driven in 
either direction, it has 31 inches of movement by hand or 
power feed, with a full bearing at all times in the cast 
iron sleeve. 

The feeds are positive, and six in number, thus permit- 
ting the spindle to be moved in either direction without re- 
versing its motion. 

The maximum distance from the top of the table to the 
centre of the spindle is 74 inches, the minimum distance is 
25 inches. 

The column has a horizontal movement on the bed of 73 
inches, the spindle carriage has a vertical movement on 
the column of 49 inches. 

The milling feeds are five in number, horizontal, vertical 
and in either direction. 

Quick traverse, by power, is provided to the column and 
spindle carriage, which are also graduated with steel rules 
for accurate adjustment. The table, upon which to place 
the work, is heavy and well ribbed and arranged with 
suitable Tee-slots. 

The support for the boring bars is mounted upon a car- 
riage, which has a rapid hand adjustment on the table, by 
means of racks and pinions, and can be securely held in 
any position. 

Horizontal Drilling Machine. The cone pulleys on the 
machine illustrated in Fig. 210 have 5 speeds for a 4-inch 
belt, it is strongly back-geared, giving 10 changes on the 
spindle, which is of cast steel 4 inches diameter, and has 
a 30-inch movement through the cone with provision for 
a 60-inch traverse when required. The steel spindle can be 
driven in either direction, it has a full bearing through the 
cast iron spindle at all times, and does not lose any of its 
bearing surface as it runs out, and has a quick movement 
by hand through a rack and pinion; there are six changes 



MACHINE TOOLS 



267 




268 MACHINE SHOP PRACTICE 

of automatic feed, three suitable for drilling and three for 
boring, by cut cone gearing, and the spindle can be fed 
in either direction without reversing its motion. 

The table is 8 feet long, elevated by screws, worm wheels 
and worms which are driven by power. The table carries a 
saddle which has a movement parallel with the main spin- 
dle. On this saddle is a cross table 36 inches by 48 inches, 
which can be lowered until its top is 33 inches from the 
centre of the spindle, and which has a horizontal move- 
ment at right angles to it. This saddle and cross table 
can be removed to increase the capacity of the machine 
when necessary. 

Vertical Boring Mill. The capacity of the machine shown 
in Fig. 211 is 44 inches in diameter and 37 inches in 
height under the cross-rail or 31 inches under the tool 
holders. 

The table is 42 inches in diameter, is powerfully geared, 
and has ten changes of speed, 5 with back gears and 5 
without. The maximum speed of the table is 20 r. p. m. 
and the minimum speed 6 r. p. m. 

The teeth of both the table and pinion are of steel, and 
are accurately planned. 

On the under side of the table there is an outer bearing 
nearly equal to the diameter of the base. 

The table spindle is 10 inches in diameter and 20 1-2 
inches in length. 

The table spindle has a straight bearing which acts in 
conjunction with an angular bearing to receive the side 
strains. There is also a thrust ball bearing on the lower 
step of the spindls which acts as a preventative against 
any lifting tendency, and which relieves the friction of 
table when a heavy cut is being taken. 

The turret slide can be set to bore, turn and cut 8 and 
11 1-2 threads per inch, and has a vertical movement of 24 
inches. 



MACHINE TOOLS 



269 




Fig. 211. 

The turret slide can be set to bore, turn and cut 8 and 
has five 2 5-16 inch holes. 

The heads are entirely independent in their movement, 
both as to direction and amount of feed. The left hand 
head can be set at any angle, and has a movement of 24 
inches. Either head can be brought to the center for bor- 
ing, both heads have a vertical movement of 24 inches. 

The heads are attached to steel feed-screws by split nuts, 
which can be opened, and a rapid movament obtained by 
ratchet and pinion, engaging a steel rack on the cross-rail. 



270 MACHINE SHOP PRACTICE 

The feeds are positive and have fifteen changes, ranging 
from 1-64 inch to 61-64 inches horizontally, and 1-64 inch 
to 9-16 inches in angular and vertical directions. 

The cross-rail is raised and lowered by power, which can 
be done without removing the table. 

The band brake which operates on the main driving cone, 
by hand, stops the table instantly. 

The back gears can be changed by means of a lever, 
without the use of a lock nut. 

Drill Presses. 

Figure 212 shows a vertical or upright drill-press, back- 
geared, with both hand and power-feeds and an adjustable 
raising and lowering swing-table. 

A is a hand-lever for the quick adjustment of the spindle 
H when using the hand-feed. B is the power-feed device 
with autotmatic stop, worm-feed and quick return motion 
for the drill-spindle. C is the step-cone pulley which is 
driven from the step-cone shown at N. D shows the bevel 
gears which transmit the motion from the horizontal shaft 
to the vertical drill-spindle D. E shows the chain to which 
a weight is attached to balance the weight of the spindle 
H. F is a hand-wheel for the hand-feed attachment on 
the worm-gear spindle. G is a quill or sleeve for raising or 
lowering the drill-spindle D, by means of a rack I attached 
to the sleeve Gf, which engages with a pinion upon the 
worm-gear spindle. J is the upright column or standard 
which carries the drill-spindle driving mechanism. K 
shows the crank for raising and lowering the table L by 
means of the bevel gears and the screw M. L is the cir- 
cular table or face-plate which is provided with slots for 
the bolts which hold down the work. R is a bracket which 
supports the table L and S a foot-lever for actuating the 
belt-shifter over the tight and loose pulleys P. T is the 
base-plate which has its upper face planed and is pro- 



MACHINE TOOLS 271 




Fig. 212. 



272 



MACHINE SHOP PRACTICE 




Fig. 213. 



vided T-slots for bolts 
to hold large work 
which cannot be drill- 
ed on the table. 

A torsional stress is 
imposed upon drill 
presses owing to the 
fact, that a revolving 
drill does not cut at 
its central point, even 
though its outermost 
circumference may 
have an excellent cut- 
ting effect. 

The torsional strain 
is easily overcome by 
using a spindle of 
high carbon steel, ac- 
curately cut gearing, 
and stiff driving 
shafts. To reach large 
work the drill head 
must overhang, and 
therefore requires a 
very strong frame to 
withstand the end 
pressure. 

Friction-Driven 
Drill-Press. 

The drill-press 
shown in Fig. 213 em- 
bodies principles not 
usually found in other 
tools of its kind, and 
is simple in construe- 



MACHINE TOOLS 273 

tion and more effective in operation than almost any other 
drill for light work. 

The speed of the drill spindle can be increased or dimin- 
ished instantly, or the motion reversed, without stopping 
the machine or shifting the belts. 

More or less driving power can be applied to the drill 
spindle, as the size of the drills or the nature of the work 
may demand. 

The feed lever is provided with a very sensitive adjust- 
ment, which with the perfect control of the operator over 
the speed and power makes it possible to use the smallest 
drills with the least possible danger of breakage. By a 
hand screw within convenient reach the platen or table can 
be moved rapidly on the column and can be clamped firmly 
at any desired height. 

All bearings and wearing surfaces are especially fitted 
for durability, and ample provision is made for taking up 
wear. 

It is claimed for this drill superiority, both in simplicity 
of the construction, which renders it less liable to derange- 
ment, and in effectiveness of operation on account of the 
variations of speed and power being so completely under 
the control of the operator, whereby all the adjustments 
are made with the least possible loss of time. It is smooth 
and almost noiseless in operation, and entirely free from 
the vibratory motion commonly found in drills of this class 
where the spindle is driven by belt. 

Gang Drill Press. Figure 214 illustrates a new pattern 
of a 3-spindle back-geared Gang Drill press, with an Auto- 
matic Approach and Return Feed. It is also made with 
spindles with or without back gear, spindle with plain lever, 
spindle with combined lever and worm feed, spindle with 
self feed and automatic stop, and with spindle with re- 
verse motion for tapping. 



274 



MACHINE SHOP PRACTICE 




Fig. 214. 

Motor-Driven Drill-Presses. 

In view of the fact that electricity is becoming 1 so popu- 
lar as a motive power for driving machinery, two methods 
or styles of mounting motors to Upright Drill-Presses are 
shown. Both illustrations (Figs. 215 and 216), show direct- 
connected electric driven tools. One is called a direct-con- 
nected Belt-Driven motor outfit, and the other a direct- 



MACHINE TOOLS 



275 




Fig. 215. 

connected Gear-Driven motor outfit. The gear-driven outfit 
has a reverse motion independent of the motor. The belt- 
driven outfit is the most popular, not only on account of 
its less cost, but from the fact that the motor is entirely 
out of the way. 



276 MACHINE SHOP PRACTICE 




MACHINE TOOLS 277 

Upright Drill. The drill press shown in Fig. 217 is said 
to be a very strong and stiff tool, thoroughl} 7 well made 
and high grade in every respect. It is made in the follow- 
ing styles: 

Without back gear, with hand lever feed. 

Without back gear, with combined lever and worm feed. 

Without back gear, with self feed, automatic stop, com- 
bined lever and worm feed. 

Back geared, with hand lever feed. 

Back geared, with combined lever and worm feed. 

Back geared, with self feed, automatic stop, combined 
lever and worm feed. 

All the drills have a quick return lever for the spindle. 

The spindle is fitted with the No. 3 Morse taper. 

Radial Drill. The radial drill shown in Fig. 218 em- 
bodies in addition to all the useful features of other ma- 
chines, several decided improvements. 

The stationary column is of heavy section throughout, 
and is made of one piece. It is bolted to the base and 
does not revolve. There are four webs inside, extending 
its entire length, which add greatly to the strength of the 
machine and provide for resisting enormous strains at any 
height, particularly when the arm and spindle are at their 
maximum distances. 

The arm is made of pipe section, its upper brace being 
as close to the ■ head as possible, while the lower brace is 
at the outer edge. This prevents twisting of the arm 
while resisting the extreme upward press are of the spindle 
when drilling. A top cap, resting on roller bearings, sup- 
ports the arm, both making a full circle about the column, 
they can be instantly locked by fixed binder levers. The 
arm is lowered at almost three times the elevating speed by 
a screw having ball thrust bearings. A bronze plate, at- 
tached to the arm, shows the operator the correct speeds 
for drilling either cast iron or steel. 



278 MACHINE SHOP PRACTICE 




Fig. 217. 



MACHINE TOOLS 



279 



A ring, graduated to 360 degrees, turns with the arm, 
and, in connection with a zero on the column, provides a 
means for bringing the arm back to a definite position as 
often as desired. This feature is of special advantage in 
working on duplicate parts held in fixed jigs or otherwise. 




Pig. 218. 

The head can be locked to the arm, it is traversed by 
means of a double pitched screw which engages with the 
revolving dial on the outer end of the arm. This permits 
the operator to bring the head to within .001 of an inch 
of the required place. 



280 MACHINE SHOP PRACTICE 

The spindle is made of crucible steel, and is ground and 
counter-balanced, it lias a quick advance and return, and 
has a provision for taking up wear. When used for tap- 
ping, it is impossible to accidentally engage either auto- 
matic or lever feed, thus avoiding the breaking of taps. 
An adjustable gauge screw causes the spindle to slip when 
a tap reaches the bottom of a hole. It requires only four 
seconds to change the spindle speed from 18 to 370 revolu- 
tions per minute, or to any of the 16 available speeds, are 
arranged in geometric progression, the maximum being 
more than 20 times the minimum. 

The starting lever projects from the loose ring encircling 
the column and is within easy reach, it " can be operated 
from any position about the machine. It controls the 
raising and lowering of the arm, also the starting, stop- 
ping and reversing of any of the 16 spindle speeds. 

The automatic feed is driven by means of a friction 
plate and by bringing the small friction wheel from the 
center to the outer diameter of this plate, any feed from 
.000 to .023 inch per revolution of spindle can be instantly 
obtained, and while the drill is at work. The amount of 
friction required for light or heavy drilling is regulated 
by a knob on the right of the feed shaft. 

The automatic trip is provided with a safety stop which 
prevents the feeding of the spindle after it reaches- the 
limit of its travel. A graduated bar on the counterbal- 
ancing weight is set to zero when the drill enters. The 
bar has several adjustable dogs to trip the feed as often as 
desired, these do not interfere with the spindle travel. The 
feed can also be tripped by a lever on the vertical feed 
rod. 

The base of the machine is deep and very heavy, with 
fan-shaped ribs leading to the center of the column. These 
ribs insure extreme rigidity, no matter where the pressure 
of the spindle may come. 



MACHINE TOOLS 



281 



The table usually furnished with the drill is plain, but a 
round or worm-swiveling table can be supplied, if desired. 
It has a round boss in its center, which can be bored to re- 
ceive bushings for boring bars passing through the center 
of the supporting stand on the base. 




Pig. 219. 

Each binder lever is forced by a small nut onto its screw, 
which has a tapered end, so that, in case of wear, it can 
be released and changed to suit the operator. 



282 MACHINE, SHOP PRACTICE 

Radial Drill. The drill shown in Fig. 219 has a sliding 
head, back geared and self-feed and automatic stop and 
quick return lever for the spindle. 

These machines are designed with a view of having all 
the adjusting parts easy of access, and so arranged that 
the operator can with the least effort control their action. 
To stop or start the spindle, to change the speed, to en- 
gage the self feed, to change from fast to slow feed, or 
from hand to self feed, to raise or lower the sliding head 
on the column, to raise or lower the platen or swing it 
from under the spindle, to throw in or out the back gearing 
— all are operated instantly by permanently attached de- 
vices for these various purposes. The drills have roller 
bearing for spindle thrust. 

Particular attention is called to the positive self feed 
with eight changes of feed, gear driven (no belts). 

The sliding head and spindle are counterbalanced, all 
shafts are of steel, and the bearings are extra long. 




Back Gear of Drill Press. The cut in Fig. 220 shows the 
cone pulley withdrawn from the shaft, and the locking 
plunger and lever for throwing in and the back gearing 
exposed to view. 



MACHINE TOOLS 



283 




284 



MACHINE SHOP PRACTICE 



This internal back gear is not new and untried, but has 
been used for fifteen years on drill presses. 

This style of back gear throws no oil, accumulates no 
dirt, is quick acting and always in working order. 

Compound Drill Press Table. 

The Drill press tables such as are illustrated in Fig. 221 
have both transverse and longitudinal feed and may also 
be swung radially around the column of the press if de- 
sired. 




Fig. 222. 

Gear change Box. The accompanying illustration Fig. 
222 shows a speed box, equipped with a constant speed 
motor, which can be furnished in place of the plain pulley 
drive. Either style speed box excels the cone pulley drive, 
because it is more easily manipulated, does away with the 
shifting of belts, and can be driven from below the floor 
or at right angles to the line shaft. The two long levers 
in front of the box control four changes of opeed, the small 
one between them locks one lever while the other is in use. 



MACHINE TOOLS 



285 



The numbers east on the lid of the box indicate in what 
direction to push the levers. They correspond with the in- 
dex plate on the arm, for the proper spindle speed. 




Fig. 223. 

Tapping Attachment for Drill Presses. 
The geared tapping attachment shown in Fig. 225 works 
directly on the spindle. It has a positive clutch for en- 
gaging the forward and backward motions and gives a re- 
verse speed of 2 to 1. A movement of the conveniently 
located lever starts, stops, and reverses the spindle in- 
stantly without any jar while the machine is in motion. 
To disengage the tapping attachment throw the lever A 
and the machine is changed from a tapping machine to an 
ordinary drill press and vice versa. There is no undue 
wear as the extra gearing is running only when required. 



286 



MACHINE SHOP PRACTICE 



Fig. 224 shows the change-speed mechanism of the feed 
of the drill presses described in Figs. 215 and 217. 

Tire Drill. The drill shown in Fig. 225 needs ve:ry little 
explanation. For drilling, boring and countersinking tires 
and rims, it is one of the most rapid and handy tools on 




Fig. 224. 

the market. By a movement of the lever, each spindle is 
brought into position and locks itself ready for action, only 
the spindle in use revolves. The hole in the spindle is 
No. 2 taper. 



MACHINE TOOLS 



287 




Fig. 225. 

: i'he arm on which the wheel rests, has rollers with ad- 
justable collars, the top rim of the wheel rests against aa 
adjustable plunger. 



288 



MACHINE SHOP PRACTICE 




Fig. 226. 



Almond Drill Chuck. 

The chuck illustrated 
in Fig. 226 will center 
and hold drills with a 
firm grip, and is said to 
be one of the best 
chucks in the market. 

Skinner Drill Chuck. 

The chuck shown in 
Fig. 227 is made entire- 
ly of steel. It is especi- 
ally adapted for all light 
and rapid drilling, such 
as is done on sensitive 
drills, and where great 
accuracy is required. 

Cushman Drill Chuck. 

The working parts c! 
the chuck illustrated in 
Fig, 228 are of steel, 
and it is made in a most 
thorough manner. It is 
a self-tightening chuck, 
and needs no spanner 
v/rench to make it hold 

Twist Drills. 

The advantages of a 
twist drill over a flat 
drill are as follows: The 
cuttings can find free 
egress more readily 
through the grooves in 
Fig. 228. the twist drill. In the 

flat drill the cuttings jamb between the hole and the wedge* 




227. 











in 



MACHINE TOOLS 



289 



shape sides of the drill, requiring frequent removal of the 
drill to extract the cuttings. In deep holes more time is 
occupied in this manner than in the actual cutting opera- 
tion. The twist drill nearly always runs true, and requires 
no reforging or tempering, and, by reason of its shape, fits 




Fig. 230. 

closely and produces a straight, parallel hole, provided the 
point is ground strictly true. 

Horizontal Drill Press. A horizontal drill press is illus- 
trated in Fig. 229. This machine is designed especially for 
large work and the drilling of holes in the end flanges of 



290 MACHINE SHOP PRACTICE 

large cast iron pipes or columns. The head is counter- 
balanced by a weight as shown and may be swung through 
a wide angular range. 

GEAR CUTTING- MACHINES. 

Fellow's Gear Shaper. A few of the distinctive features 
of the machine shown in Fig. 230 are: The gear shaper 
cuts a theoretically correct gear tooth. Only one cutter 
for each pitch is necessary. An error in spacing is an 



Fig. 231. 

impossibility. No depth gauge is required, as the machine 
attends to that automatically. It cannot produce an in- 
correct tooth by setting the cutter "off center. " The cutter 
travels the exact face of the blank only. The gear shaper 
is furnished with an equipment covering all of the ordi- 
nary needs of a machine of this kind, including an auto- 
matic cutter grinder, a set of six cutters, change gears, oil 
pump and countershaft. 



MACHINE ..XQQkb 



291 



An example of the work produced is shown in Fig. 231. 
This is done as follows: The blank to be cut is securely 
fastened on the work arbor and the machine being started, 
the cutter reciprocating vertically on its center line is fed 
towards the blank A, and cuts its way to the proper depth. 
At this point both the cutter C and the blank G begin to 
revolve, the cutter C maintaining its reciprocating motion. 




Pig. 232. 



This revolution of the cutter C and the blank G is ob- 
tained by an external mechanism, which insures that the 
movement shall be as though the cutter and blank were 
two complete gears in correct mesh. Fig. 232 is a section 
through the blank and cutter which shows the process of 
cutting spur-toothed gear wheel. 

It also shows the action of the gear cutter, each cut and 
the wedge form of the gear shaper chips. 



292 



MACHINE SHOP PRACTICE 



The combined result of the rotary and reciprocating mo- 
tion is that the cutter teeth generate conjugate teeth in the 
blanks which mesh correctly with the cutter teeth and with 
each other. 

Whiton Gear Cutter. The tool shown in Fig. 233 is a 
universal milling machine, which is adapted for cutting 




Pig. 233. 



spur and bevel gears, and worm gears by the bobbing pro- 
cess, from blanks not previously nicked. 

Every movement depends for its action upon the comple- 
tion of all previous movements, so that the possibility of 
error is reduced to a minimum. 

The feed depends upon the completion of the spacing, 



MACHINE TOOLS 



293 



and the cutter cannot advance into an imperfectly spaced 
blank. The feed mechanism is disengaged during the spac- 
ing, and the cutter carriage remains at rest. The spacing 
movement is very rapid, and its completion re-engages the 
feed. Only one stop adjustment is required. 




Fig. 234. 



There are no frictional devices which consume power 
when not in action. 

Automatic Gear Cutter. The machine shown in Fig. 234 
cuts spur gears to 26 inches in diameter; 8 inches face 



294 MACHINE SHOP PRACTICE, 

and 4 diametral pitch in cast iron and 5 in steel. The 
cutter spindle is hardened and ground and provided with 
means of compensation for wear. It has 6 changes of 
speed from 20 to 80 revolutions per minute. The speed 
changes are in geometrical progression and are obtained 
by change gears. The outer bearing on the cutter slide 
gives an additional support to the cutter arbor. 

The eutter arbor is iy 2 inches in diameter, it can be re- 
moved in a few moments and smaller ones substituted. 
The return of the cutter slide is rapid and at a constant 
speed which is independent of the speed and feed of the 
cutter. The cutter has 15 changes of feed from .037 to 
.620 inches per revolution and is obtained by change gears. 
The feed changes is geometrical progression. The work 
spindle head is adjusted by means of a screw operated by 
a crank. The thrust of the elevating screw is taken by 
ball-bearings. A dial graduated to thousandths of an inch 
indicates the amount of this adjustment. Provision is also 
made for raising and lowering the head by power. The 
indexing mechanism is extremely accurate and entirely in- 
dependent of the feed and speed of the cutter, so that the 
indexing is as rapid when the feed and speed are slow as 
when they are fast. The index change-gear provide for the 
cutting of all numbers from 12 to 50 and all numbers from 
50 to 400 excepting prime numbers and their multiples. 

The Sizing and Cutting of Gears. The word diameter 
when applied to gears is always understood to mean pitch 
diameter. 

The diametral pitch of a gear is the number of teeth 
to each inch of its pitch diameter. 

If a gear has 40 teeth and the pitch diameter is 4 inches, 
there are ten teeth to each inch of the pitch diameter, 
and the diametral pitch is 10, or, in other words, the gear 
is 10 diametral pitch. 

The circular pitch is the distance from the center of 



MACHINE TOOLS 295 

one tooth to the center of the next tooth, measured along 
the pitch circle. 

If the distance from the center of one tooth to the cen- 
ter of the next tooth, measured along the pitch circle, is 
y 2 inch, the gear is ^2 inch circular pitch. 

Having the diametral pitch, to obtain the circular pitch, 
divide 3.1416 by the diametral pitch. 

If the diametral pitch is 4, divide 3.1416 by 4, and the 
quotient, 7854, is the circular pitch. 

Having the circular, to obtain the diametral pitch, divide 
3.1416 by the circular pitch. 

If the circular pitch is 2 inches, divide 3.1416 by 2 and 
the quotient 1.5708, is the diametral pitch. 

Having the number of teeth and the diametral pitch, 
to obtain the pitch diameter, divide the number of teeth 
by the diametral pitch. 

If the number of teeth is 40 and the diametral pitch is 
4, divide 40 by 4, and the quotient 10, is the pitch dia- 
meter. 

Having the number of the teeth and the diametral pitch, 
to obtain the whole diameter or size of blank of the gear, 
add 2 to the number of teeth, and divide by the diametral 
pitch. 

If the number of teeth is 40 and the diametral pitch 
is 4, add 2 to the 40, making 42, and divide by 4; the 
quotient, IOV2, is the whole diameter of the gear or blank. 

Having the number of the teeth and the diameter of the 
blank, to obtain the diametral pitch add 2 to the number 
of the teeth, and divide by the diameter of the blank. 

If the number of teeth is 40, and the diameter of the 
blank is 10 V> inches, add 2 to the number of teeth making 
42, and divide by lO 1 /^ The quotient, 4, is the diametral 
pitch. 

Having the pitch diameter and the diametral jritch, to 
obtain the number of teeth, multiply the pitch diameter by 
the diametral pitch. 



296 MACHINE SHOP PRACTICE 

If the diameter of the pitch circle is 10 inches, and the 
diametral pitch is 4, multiply 10 by 4, and the product, 40, 
will be the number of teeth in the gear. 

Having whole diameter of the blank and the diametral 
pitch, to obtain the number of teeth in the gear, multiply 
the diameter by the diametral pitch and substract 2. 

If the whole diameter is lO 1 /^, and the diametral pitch is 
4, multiply 10y 2 by 4 and the product, 42 less 2, or 40, is 
the number of teeth. 

To obtain the thickness of a tooth at the pitch line, 
divide the circular pitch by 2f, or divide 1.57 by the diame- 
tral pitch. 

If the circular pitch is 1.047 inches or the diametral 
pitch is 3, divide 1.047 by 2, or 1.57 by 3, and the quotiert, 
.523 inch, is the thickness of the tooth. 

To obtain the whole depth of a tooth, divide 2.157 by 
the diametral pitch. 

If the diametral pitch of a gear is 6, the whole dep^h is 
2.157 divided by 6, equals .3595. 

The whole depth of a tooth is about 11-16, or exactly 
.6866 of the circular pitch. 

If the circular pitch is 2, the whole depth of the tooth is 
about 11-16 of 2 inches, or 1 3-8 inches nearly. 

To obtain the distance between the centres of tv d gears, 
add the number of teeth together, and divide half the sum 
by the diametral pitch. 

If two gears have 50 and 30 teeth, respectively, and are 
5 pitch, add 50 and 30, making 80, divide by 2, and then 
divide this quotient, 40, by the diametral pitch, 5, and the 
result, 8 inches, is the centre distance. 

To divide the sum of the pitch diameters of the gears 
by 2. 

No. 13 table shows the diametral pitches with the corre- 
sponding circular pitches . 

No. 14 table shows the circular pitches with the corre- 
sponding diametral pitches. 



MACHINE TOOLS 



297 



Table No. 13. 


Table 


No. 14. 


Diametral Pitch. 


Circular Pitch, in 
inches. 


Circular Pitch, in 
inches. 


Diametral Pitch, 
in inches. 


IX 


2.5133 


2 


1.571 


IX 


1.0944 


1% 


1.676 


1% 


1.7952 


1% 


1.795 


2 


1.571 


1% 


1.933 


2% 


1.396 


IX 


2.094 


2% 


1.257 


1* 


2.185 


2% 


1.142 


1% 


2.285 


3 


1.047 


1* 


2.394 


3X 


.898 


lX 


2.513 


4 


= 785 


lfV 


2.646 


5 


.628 


IX 


2.793 


6 


.524 


ItV 


2,957 


7 


.449 


i 


3 = 142 


8 


.393 


1 5 
Tfi" 


3.351 


9 


.349 


X 


3.590 


10 


.314 


1 3 

T"6" 


3.867 


11 


.286 


% 


4.189 


12 


.262 


1 1 


4.570 


14 


.224 


% 


5.027 


16 


.196 


9 
TIT 


5.585 


18 


.175 


X 


6.283 


20 


.157 


7 
TTT 


7.181 


22 


.143 


V 

/8 


8.378 


24 


.131 


5 
TB" 


10.053 


26 


.121 


X 


12.566 


28 


.112 


3 

TT5" 


16.755 


30 


.105 


X 


25.133 


32 


.098 


tV 


50.266 


36 


.087 






40 


.079 






48 


.065 







According to the system adopted by the Brown & Sharpe 
Mfg. Co., and known as the Diametral Pitch System, any 
gear of one pitch will gear into any other gear or into a 
rack of the same pitch. Eight cutters are required for 
each pitch. These eight cutters are adapted to cut from 



298 MACHINE SHOP PRACTICE 

a pinion of twelve teeth to a rack, and are numbered re- 
spectively, 1, 2, 3, &c. 



No. 


1 will cut wheels from 135 teeth to 


a rack. 


No. 


2 will cut wheels from 


55 teeth to 134 teeth. 


No. 


3 will cut wheels from 


35 teeth to 


54 teeth. 


- No. 


4 will cut wheels from 


26 teeth to 


34 teeth. 


No. 


5 will cut wheels from 


21 teeth to 


25 teeth. 


No. 


6 will cut wheels from 


17 teeth to 


20 teeth. 


No. 


7 will cut wheels from 


14 teeth to 


16 teeth. 


No. 


8 will cut wheels from 


12 teeth to 


13 teeth. 



If a cutter is wanted for a wheel of 40 teeth of 8 pitch, 
then the cutter required, would be No. 3 of 8 pitch, inas- 
much as a No. 3 cutter will cut all wheels containing from 
35 to 54 teeth, inclusive, and 40 occurring between those 
numbers, it is the one desired. It should be borne in mind 
that eight different cutters are required in order to cut all 
the wheels of any given pitch. 

As these cutters allow of being ground when dull, it is 
important that they be kept sharp. By paying particular 
attention to this the cutting will be greatly facilitated be- 
side being much better done. 

It is desirable in applying gearing of any kind, to avoid 
having wheels or pinions with a small number of teeth. 
Pinions of twelve teeth will work very well but a less num- 
ber of teeth should not be used. 

Few mechanics are familiar with the minutiae of gearing 
and the necessity of exact sizing of wheels, as to diameter, 
is often overlooked. Special care is required also to know 
what the distance of the centers of two wheels running 
together is correct relative to the diameters. 



MACHINE TOOLS 



299 



Table No. 15— 


Depth op 


Space 


and Thickness of 




rOOTH IN 


Spur Wheels, when cut with 






Involute 


Cutters. 


Pitch 

of 
Cutter. 


Depth to be 

cut in Gear, 

in inches. 


Thickness of 
Tooth at 
Pitch Line, 
in inches. 


Pitch 

of 
Cutter, 


Depth to be 

cut in Gear, 

in inches. 


Thickness of 
Tooth at 

Pitch Line, 
in inches. 


l x A 


1.726 


1.257 


11 


.196 


.143 


IX 


1.438 


1.047 


12 


.180 


.131 


1% 


1.233 


.898 


14 


.154 


.112 


2 


1.078 


.785 


16 


.135 


.098 


2% 


.958 


.697 


18 


.120 


.087 


2% 


.863 


.628 


20 


.108 


.079 


2% 


.784 


.570 


22 


.098 


.071 


3 


.719 


.523 


24 


.090 


.065 


3X 


.616 


.448 


26 


.083 


.060 


4 


.539 


.393 


28 


.077 


.056 


5 


.431 


.314 


30 


.072 


.052 


6 


.359 


.262 


32 


.067 


.049 


7 


.308 


.224 


36 


.060 


.044 


8 


.270 


.196 


40 


.054 


.039 


9 


.240 


.175 


48 


.045 


.033 


10 


.216 


.157 









Cutting Gears. When cutting gears care must be taken 
to have the cutter central with the index centers, and to 
have the cut exactly the depth required. A good method 
of testing the setting is to cut a groove in a piece on the 
centers, then shift the piece end for end and try the groove 
upon the cutter. A good method of holding the gear blanks 
is on an arbor with a taper shank which fits in the index 
spindle, the outer end of the arbor being supported by the 
foot stock center. Frequently in cutting gears a shank 
arbor is used with an expanding bushing and a nut on the 
arbor at each end of the bushing, one nut forcing the bush- 
ing up on the arbor and holding the gear blank, while 
the other pushes the bushing off the taper and releases 



300 MACHINE SHOP PRACTICE 

the gear when finished. If the ordinary arbor and dog are 
used, care must be taken that the dog does not spring the 
arbor. The depth of the cut can be gauged from the out- 
side of the blank, or, if so desired, marked on the side by 
a gear tooth depth gauge. In cutting gears, when the blank 
has been placed in position it is raised by the elevating 
screw until it just touches the cutter. The graduated col- 
lar on the vertical feed shaft is placed on the zero line 
and the blank moved horizontally away from the cutter. 
Then the work is raised the number of thousandths of an 
inch required for the depth of tooth. 

Table No. 15 gives the depth of the gear teeth of pitches 
from 1^4 to 48 diametral pitch. Directions regarding the 
sizing and cutting of gear wheels, formulae for determin- 
ing the dimensions of small gears by diametral pitch, also 
directions for selecting involute gear cutters for any given 
pitch are also given in connection with the table. 

Tooth Flanks Undercut. It is well known that involute 
gears can be made of different systems or of different 
angles of obliquity or pressure. In the system proposed 




Pig.235A 

by Professor Willis about fifty years ago, the angle of pres- 
sure, or obliquity, is fourteen and a half degrees. Twice 
this angle is the familiar angle of a Avorm thread tool. 
Gears made upon this system are thought to crowd less 
upon their shafts than those having a greater angle of 
pressure. If, however, a gear or pinion has fewer than 



MACHINE TOOLS 301 

twelve teeth, this angle may cause their flanks to be un- 
dercut and in consequence weak in order to clear the faces 
of the teeth of the engaging gear. The drawing of a seg- 
ment of a gear of ten teeth, four diametral pitch, in Fig. 
235A, illustrates this undercutting which is greater as the 
teeth are fewer. 

Gears or pinions, having fewer than twelve teeth might 
be unavailable if undercut as much as at A, B and C, in 
Fig. 235B. Gears that are to do heavy work may require 
a greater angle of pressure than fourteen and a half de- 
grees, if they are to run with a pinion of fewer than 
twelve teeth. 




Fig. 235B 

In the choice of an angle of pressure some idea may be 
obtained from the lower view in which is taken from a 
gear 10 teeth, 4 diametral pitch. The angle of pressure in 
these teeth is 22y 2 degrees. The greater strength of the 
tooth flanks in this figure is readily seen. The angle can- 
not be much more than thirty-two degrees and have the 
addendum of the teeth or that part of the tooth above 
pitch line of the ordinary height, which is equal to one part 
of the diametral pitch. 

Bevel Gears. The curve of the teeth in bevel gears, 
when correctly formed, changes constantly from one end of 
the tooth to the other. Consequently bevel gears, whose 
teeth are produced with a cutter of fixed curve, are not 



302 MACHINE SHOP PRACTICE 

theoretically correct, the cutter usually being of a curve 
that will make the correct form at the outer part of the 
face of the gear, and of necessity will leave the curves too 
large at the inside ends of the teeth. Small bevel gear- 
ing is almost universally produced in this manner, which 
practically answers the purpose, except when the teeth are 
very coarse or the gears very small, in which cases their 
operation is not satisfactory. In place of cutting by chang- 
ing the position of the cutter, the teeth are often filed 
slightly, in order to round them off to the curve required 
for their free running. On all bevel gears cut with a 
cutter of fixed curve, it is necessary to cut through twice, 
owing to the necessity of making the thickness of the cut- 
ter on the pitch line equal to about .005 inches thinner 
than the space between the teeth at the smallest Pitch dia- 
meter. As the width of space between the teeth on the 
largest pitch diameter should be greater than the thickness 
of the cutter, it must be made so by passing that cutter 
through the second time. Pig. 236 will explain the forms 
of spur, bevel and mitre gears, also the terms pitch diame- 
ter, outside diameter, largest pitch diameter, length of face, 
etc. When a pair of bevel gears are of same size and 
number of teeth, with their lines of centers at right angles, 
they are called mitre gears, and one cutter will answer for 
both, but where one gear has a greater number of teeth, 
or differs in bevel from the one running into it, then each 
of the pair of gears may require a different cutter. 

When giving the dimension for bevel gears always give 
the following information as shown in Fig. 237. 

The pitch, or if preferred, give the diameter of pitch cir- 
cle. 

The number of teeth in the gear. The number of teeth in 
the pinion. 

A, or diameter of hole in the gear, a, or the diameter of 
the hole in the pinion. 



MACHINE TOOLS 



30S 



The backing for both the gear and pinion^ 
C. or width of the face. 




LARGEST PITCH DIAM 
Fig. 236. 



T), or diameter of the gear hub, or the diameter of the 
pinion hub, if these dimensions are of importance. 



304 



MACHINE, SHOP PRACTICE 



E, or the distance from center of pinion shaft to end of 
gear hub; or distance from center of gear shaft to end of 
pinion hub. 

Key way, or set screw, and what size. 




Fig. 237. 



Whether to be used for pattern or not. 

Does the pinion drive or is it driven. 

Comparative sizes of gear teeth. The illustration in 
Fig. 238 show the comparative size of the teeth of involute 
gears from 20 to 3 diametral pitch. The teeth shown in 
the drawing are the full or actual size. 

Gear Tooth Caliper. The double vernier caliper shown 
in Fig. 239, is for the purpose of accurately measuring the 
distance from the top of the teeth to the pitch line, and 



I 







-. 



Iv-W 




; j. 



% •:• 



•- . 




MACHINE TOOLS 



305 



the thickness at the pitch line of gear teeth. I will mea- 
sure all pitches. 

The sliding jaw moves upon a bar graduated to read by 




Fig. 239. 

means of the vernier to thousandths of an inch. A tongue, 
moving at right angles with the jaws, is graduated in the 
same manner. Both the sliding jaw and tongue are pro- 
vided with suitable adjusting screws. 



306 



MACHINE SHOP PRACTICE 



GRINDING MACHINES. 

Grinding Machines have proved to be well adapted for 
producing accurate work. Not only have they proved econ- 
omical in the manufacture of machinery and tools, both 




Fig. 240. 



general and special, but for duplicating parts of machinery 
manufactured on the interchangeable system, they are un- 



MACHINE TOOLS 



307 



excelled. They produce the same degree of accuracy, ex- 
cellence, and economy when used on either hardened or soft 
work. 




Pig. 241. 

That it costs much less to finish and fit work by grinding 

with emery wheels than by the old method on the lathe, 

has been repeatedly proven by experience. As emery 

wheels, for a given amount of work, cost less than files 



308 



MACHINE SHOP PRACTICE 



and emery cloth, it may be seen that this saving, together 
with the reduction in the time required to do the work, is 
a material one, whether the grinding is done for making 
accurate fits, or rough sizing. In many instances, actual 
practice shows that soft steel can be worked to much bet- 
ter advantage on the grinding machine than in the lathe 
or the milling machine. 




Pig. 242. 

Automatic Saw Grinder. The machine shown in Fig. 240 
will automatically grind the teeth of saws from 16 to 54 
inches diameter. 

Bench Grinder. The machine illustrated in Fig. 241 will 
be found one of the most useful and convenient tools in 
the shop. The emery wheel head is adjustable to any de- 



MACHINE TOOLS 



309 



sired position for throwing light on the work while being 
ground. By filling the basin with water, it keeps the emery 
from flying and also provides a convenient place to dip the 
tools in while grinding. 

Grinding Attachment. Figure 2*42 illustrates a new 
motor, driver, lathe, planer or shaper grinding attachment 
to be placed in the tool post of the lathe. The efficiency 
of this machine can be readily seen by anyone requiring 
grinding to be done in the lathe. An attachment goes with 
each machine for internal grinding, as well as external. 




Fig. 243. 

Knife Grinding Machine. The machine illustrated in 
Fig. 243 is particularly adapted for any size and style of 
straight knives. It is provided with a friction clutch, 
which admits of starring and stopping the carriage quick- 
ly without stopping the belts. The bed and base are cast 



310 MACHINE SHOP PRACTICE 

in one piece, thereby making a very rigid machine, where 
rigidity and cleanliness are particularly required. 




Fig. 244. 

Size of the emery wheel, 26xiy 2 inches. The size of the 
emery wheel pulleys, tight and loose, 10^x4% inches. The 



MACHINE TOOLS 311 

size of the carriage gang pulleys, 9x2y 2 inches. The speed 
of the emery wheel per minute is 356 revolutions. The 
speed of the carriage per minute is 10y 2 feet. 

Motor Driven Drill Grinder. This machine shown in Fig. 
244 is desirable wherever an electrical plant has been in- 
stalled. It is made both for 110 and 220 volts. 

This machine, as is clearly shown, has the motor frame 
and stand cast in one piece, the controlling switch being 
located within the hollow column, and is operated by the 
handle shown on the side. The motor is very solidly made, 
and will stand rough usage. The bearings are self oiling 
and are extra large to insure long life. The bushings are 
made of gun metal and are easily renewed. 

One advantage possessed by an electrically driven drill- 
grinder is that it may be located at any place desired, and 
quickly connected with the power circuit by wires which 
can be led in any direction. It needs no pulleys, counter- 
shaft or belting, and when once installed, the cost of main- 
tenance is reduced to a minimum. 

Motor Driven Water Grinders. The motor-driven grind- 
er shown in Fig. 245 is very neat and compact. Every 
machine is set up and tested for several hours before ship- 
ping. They can be furnished to operate with direct or 
alternating current. 

PLAIN GRINDING MACHINES. 

The grinding machine shown in Fig. 246 is unusually 
heavy, and the metal is so 'disposed as to obtain a maxi- 
mum strength, and reduce the vibration, which is so com- 
mon in this class of machines, to a minimum. 

The Spindle is of the best machinery steel, turned and 
ground to size. The ends are provided with threads of 29 
degree angle, of the same depth as, but stronger than the 
square thread generally used. 

The Bearings are unusually large and are placed as near 
the wheels as practicable, thus reducing the liability of 



312 MACHINE SHOP PRACTICE 

vibration. They are dust proof. The larger size grinders 
are provided with renewable, inter-changeable boxes. The 




Fig. 245. 

caps are tongued and grooved, making them rigid and not 
Uable to work loose. 

The Flanges are heavy and of large diameter. The tight 



MACHINE TOOLS 



313 



flanges are forced on the spindle, and provided with grooves 
arranged to prevent the entrance of dust or dirt to the 
bearings from the outer ends of the boxes. 

The Self -Oiling Arrangement insures a plentiful supply 
of oil, and is of such construction that it is impossible for 
any dust, grit or sediment to reach the bearings. Reser- 
voirs are provided underneath the spindles for holding oil, 




Fig. 246. 



which is fed to the bearings by means of a "wiper." The 
wiper is pressed up by a brass spring, and kept constantly 
in contact with the spindle. 

Polishing or Grinding Machine. The machine illustrated 
in Fig. 247 is so constructed that emery or polishing wheels, 
even though out of balance, will revolve on their center of 
gravity and will run smoothly, and will not rjound. 



314 MACHINE SHOP PRACTICE 

Polishing wheels do not require balancing when run on 
this machine, and will retain their coating of emery much 
longer than on the ordinary machine. The work will not 
bump or stutter on the wheel, but passes over smoothly, 
and any wavy appearance of work is entirely obviated. 

The bearings are so constructed that they can be m^rtz 




Fig. 247. 

pliable and elastic, or rigid, according to the demands rf 
the operator, and the machine can be run at double *he 
speed of the ordinary machine without heating. 

Saw Grinder. The machine illustrated in Fig. 248 will 
grind circular or rip saws from 14 inches to 73 inches, and 
any shape or size of tooth. It has an adjustable stop screw 
to regulate the depth of the teeth. Size of the wheel, 12 
inches, any thickness to fit the tooth. 

Surface Grinder. The hand surface grinder shown in the 
drawing at Fig. 249 is an extremely useful tool for grind- 
ing small work. 



MACHINE TOOLS 



315 



Universal Grinding Machines. The grinder shown in 
Fig. 250 is an electrically driven tool in even- detail, as 

both the motor and 
machine are designed 
to work together and are 
built and tested in the 
same shop. Universal 
grinders, from the pecu- 
liar nature of their 
work, are better adapted 
to this mode of driving 
than most other ma- 
chine tools, having as 
they usually do from 
eight to ten belts, some 
of which have to. be re- 
moved for almost every 
operation. The belts 
not in use hang in the 
way and are always giv- 
ing more or less trouble 
when running at a high 
speed. The work of a 
universal grinder re- 
quires that either the 
wheel or the piece be- 
ing operated on should 
occupy almost every 
conceivable position. 
This is much easier 
and more quickly done 
where the wheel is made 
to move. Practically 
all work is held between 
Fig. 248. a pair of plain centers, 

or in a vise, and the wheel moved instead of the work, thereby 
making a large saving in time. 




316 



MACHINE SHOP PRACTICE 



The machine shown in Fig. 251 is a universal surface 
grinding machine with hand instead of power feeds. The 
longitudinal feed is by a lever as shown and the cross or 
transverse feed by means of a hand-wheel. A taper grind- 




Fig. 249. 



ing attachment is provided which is operated by a hand- 
wheel and screw at the left of the hinged table. 

Water Grinding Attachment. The Water Attachment 
as shown in Fig. 252 is arranged for use on the grinder 
heads. It is so constructed that the outside covering plates 
can be easily removed, and access quickly had to the 



MACHINE TOOLS 



317 



wheels. The tool rests and the plates for deflecting the 
water are adjustable to the wear of the wheel. 

Water Grinding Machine. The water attachment on the 
machine illustrated in Fig. 253 consists of a chain and 




Fig. 250. 



pulley, entirely clear of the water in the tank, and is oper- 
ated by simply lowering the lever on the side when a flow 
of water is desired, and raising it to turn it off. There is 
no pump to get out of order, nor pan to rust fast. The 



318 



MACHINE SHOP PRACTICE 



entire attachment can be reached in a minute's time. The 
flow is even and constant and the operator is not deluged. 
Water Tool Grinder. A water tool grinder is shown in 
"Fig. 254 has an outside attached centrifugal pump to fur- 
nish a supply of water to the wheel. The water is collaatf 
ed in the base of the grinder and is used over again. 




Pig. 251. 

Care and Use of Grinding Machines. As the durability 
of a machine very largely depends upon the care of the 
operator, it will soon become unreliable if not properly 
cared for, however well it may have been constructed. All 
wearing surfaces should be carefully guarded and kept well 
supplied with oil. The use of a good quality of any ma- 



MACHINE TOOLS 319 

chine oil is recommended in preference to one of a low 
grade. Oil holes which are closed with screws usually 
have the words oil hole stamped around them, and care 
should be used when oiling to keep them free from dirt and 
emery grit. 



Fig. 252. 

The grinding machines should be kept as clean as pos 
sible, and in no case should the bearings be allowed to 
gum up. Wttien the bearings are opened and exposed for 
any purpose whatever, they should be carefully wiped off 
before they are closed again to free them from any grit 
that may have lodged upon the surfaces. 

The spindle boxes should be perfectly clean when put 
together. Before tightening the caps the oil space should 



320 MACHINE SHOP PRACTICE 

be filled with good oil, never lard oil, and the wheel turn- 
ed slowly while first one cap and then the other is screw- 
ed down until quite tight. The felt that supplies the oil to 
the spindle should be kept clean. 



Fig. 253. 

Water should always be used on such classes of work as 
are affected by a change of temperature caused by grind- 
ing. It should also be used upon work revolving upon cen- 



MACHINE TOOLS 



321 



ters, as in this class of work a slight change in temper- 
ature will cause the wheel to cut on one side of the piece 
after it has been ground apparently round. 




Pig. 254. 
In very accurate grinding water is especially useful, for 
the exactness of the work will be affected by a change in 
temperature which is not perceptible to the touch. It is 
well to use the water over and over again, as there is thus 
less difference between the temperature of the water and 
the work than if fresh water is used. 



P22 MACHINE SHOP PRACTICE 

Work that will grind smooth with water will often de- 
velop minute vibrations when grinding dry. There is, ap- 
parently, a rapid fluctuation of temperature, which causes 
the work to approach and recede from the wheel very rap- 
idly, thus leaving a mottled or rough surface. 

Emery Wheels. Wheel should always be kept true. This 
can be easily done by using a diamond tool, known as the 
black diamond or carbon point, held in the hand or in the 
fixture furnished with the machine. A new emery wheel 
should be started slowly and trued gradually. Fig. 255 
shows the method of truing the face and the side of the 
wheel. 

In mounting emery wheels there should always be elastic 
washers placed between the wheel and the flanges. Sheet 
rubber is the best for this purpose, but soft leather will 
answer very well. In some eases manufacturers of emery 
wheels attach thick, soft paper washers to each side of the 
wheel, when this is done it is all that is necessary. 

A satisfactory emery wheel is an important factor in the 
production of good work. Too much, however, must not be 
expected of one wheel. A variety of shapes, sizes, and 
grades of wheels is necessary for the grinding machine, the 
same as a variety of shapes and sizes of tools are necessary 
to obtain the best results from the lathe or milling ma- 
chine. 

Internal Grinding. For internal grinding it is especially 
important that a wheel should be free cutting, and the work 
revolved so slowly as to enable the wheel to readily do its 
work. The wheels should generally be softer than for ex- 
ternal grinding, as a much larger portion of the periphery 
is in contact with the work. In regulating the speed of 
the work it must always be considered that the small dia- 
meters of the wheels make it impossible to obtain the 
proper periphery speed. 



MACHINE TOOLS 



323 




Pig. 255. 



324 MACHINE SHOP PRACTICE 

The method of driving an internal grinding fixture is 
illustrated in Fig. 256. 

Speed of the Work and Cut of the Wheel. The speed 
of the work and cut of the wheel bear such close relation 
to each other that it is best to consider them together. 
The surface speed of the work should be proportional to 
the grade and speed of the wheel. For example, if a piece 

1 inch in circumference is being ground successfully with 
a given wheel, and the wheel is sizing accurately in re- 
sponse to the graduations on the cross feed wheel a piece 

2 or 3 inches in circumference would, with the same wheel 
and number of revolutions per minute show a coarser sur- 
face, and the wheel would cut larger than shown by the 
graduations on the cross feed wheel. On the other hand, 
if the same surface speed was used in both cases the re- 
sults would be the same. 

Should a wheel heat or glaze, more effective work can 
often be obtained by running it slower. If, on the other 
hand, it is too soft it can often be made to hold its size, 
and grind straight, by using a higher speed. 

Method of Driving Universal Grinder. The elevation. 
Fig. 257, shows the location of the overhead works in rela- 
tion to the grinding machine. The shafts run in the direc- 
tion indicated by the arrows. The emery wheel is controlled 
by the main belt shipper and the work is revolved independ- 
ently of the wheel. 

Accuracy of the Work. In order to reduce the diameter 
of work as little as one-quarter of one-thousandth of an 
inch, the emery wheel slide must move as little as one- 
eighth of one-thousandth. If it were possible to split a 
piece of tissue paper into twelve thicknesses, one of 
them would represent the movement of the wheel slide re- 
quired to reduce the diameter of work one-quarter of one- 
thousandth of an inch, an amount that is scarcely visible 
to the naked eye. The wheel slide to move such a small 



MACHINE TOOLS 



325 




326 



MACHINE SHOP PRACTICE 




Pig. 257. 



MACHINE TOOLS 



327 



amount accurately, must be well oiled each day, and to in- 
sure thorough lubrication, it should be moved its entire 
length while oiling. 




Fig. 258. 

Back Rest. A plain back rest as shown in Fig. 258 may 
be used to advantage on all grinding operations where its 
use will increase the steadiness of the work. 

Soft metal shoes made to fit various diameters, are the 
best. The shape of these shoes can be varied to suit 



328 



MACHINE SHOP PRACTICE 



special work. As a rule, however, back rest shoes must be 
more or less special and dependent upon the judgment of 
the operator. 

Head Stock. A cross section through the headstock of 
a grinding machine is shown in Fig. 259. The boxes are 
usually adjusted before the machine is boxed for shipment, 
and, ordinarily, no adjustment for wear will be required 
for several years after the machine has been in opera- 
tion. When any adjustment for wear is required, remove 
the caps and scrape a small amount from the seats where 
they bear upon the head casting when in place. Then re- 




iiliiiinii ,i i I i i i i ■ I ■ i.i .ii ill. 



20 30 40 SO 0070 



Pig. 259. 

place the caps and force them to their seats with the bind- 
ing screws. When it is desired to grind the work on the 
dead centers the spindle is held in position by a pin, as 
shown in Fig. 259. 

Vibration of the Work. Vibration or chatter of the 
work is the cause of much trouble if means of prevention 
are not understood. In a well designed and constructed 
machine the vibration of its parts should be reduced to a 



MACHINE TOOLS 



329 




330 MACHINE SHOP PRACTICE 

minimum, and provision made for changes of speed to help 
to avoid this difficulty. The wheel journals must also be a 
very tight fit in the boxes and the wheel belt should be 
spliced and glued. The use of rivets to fasten the belt 
should be avoided. 

Grinding Work on the Head-Stock. Truing Centers. 
The accuracy of all work ground on centers is so dependent 
upon the centers being true that the operation of truing the 
centers by grinding should be frequently performed. To 
grind or true a center it is only necessary to set the head- 
stock to the proper angle by means of the graduations on 
the base. 

Wheel Spindle and Boxes. The wheel spindle and boxes 
or journal bearings are shown in section in Fig. 260. 

Adjustment for the end play of the spindle is made by 
means of a nut, which is held in position by a check screw. 

The boxes are adjusted by two nuts, to compensate for 
wear both the nuts should be turned toward the back of 
the machine. 

The spindle and boxes can be removed from the wheel 
stand without disturbing the adjustment of the boxes. 
Loosen the caps, which are hinged and held in place by 
bolts. 

The driving pulley and flange are made in one piece, and 
fitted to the spindle and held in place by a lock nut on the 
spindle. 



MACHINE TOOLS 



331 



Table No. 16 — Emery Wheel Speeds. 




For Surface 

Speed of 5000 

feet 


For Surface 

Speed of 6000 

feet. 


For Surface 

Speed of 7000 

feet. 


For Surface 

Speed of 8000 

feet. 


Dia. in 
Inches 


Revolutions 
per minute. 


Revolutions 
per minute. 


Revolutions 
per minute. 


Revolutions 
per minute. 


1 


19098 


22918 


26737 


30557 


2 


9549 


11459 


13368 


15278 


3 


6366 


7639 


8912 


10185 


4 


4774 


5729 


6684 


7639 


5 


3819 


4583 


5347 


6111 


6 


3183 


3819 


4456 


5092 


7 


2728 


3274 


3819 


4365 


8 


2387 


2864 


3342 


3819 


10 


1909 


2291 


2673 


3055 


12 


1591 


1909 


2228 


2546 


14 


1364 


1637 


1909 


2182 


16 


1193 


1432 


1671 


1909 


18 


1061 


1273 


1485 


1697 


20 


954 


1145 


1336 


1527 


22 


868 


1041 


1215 


1388 


24 


795 


954 


1114 


1273 


30 


636 


763 


891 


1018 


36 


530 


636 


742 


848 













332 MACHINE SHOP PRACTICE 



THE LATHE. 

The lathe, as is well known, is the principal machine 
tool of today. But the lathe has in the last few years 
undergone many improvements and transformations, thus 
widening its scope and very greatly extending and expedit- 
ing its operations. The screw machine and the current 
lathe are but one form of lathes designed to produce cer- 
tain classes of work more rapidly and with a minimum 
amount of skill in the operator. 

The simplest form of lathe consists of a bed or shears, 
carrying a head stock for driving the work and a tailstock 
or footstock for supporting the work at the other end. The 
headstock is secured firmly to the shears, while the tail- 
stock is made movable along it so that it may be moved 
up until the dead center meets the end of the work which 
is supported at the driving end by the live center. 

Erecting Lathes. Erect the lathe on a good floor. It is 
essential that the floor be free from vibrations, and stiff 
enough so that it will not give under the weight of the 
lathe. Where possible a stone or concrete foundation will 
answer the purpose much better. When levelling use only 
solid packing under the legs. Level the bed in both direc- 
tions, using an accurate level. It is most important to have 
the level show the same when placed across the shears at 
both the head and tail end of bed. If the level is not long 
enough to reach across the* shears, place it on a good paral- 
lel strip. For accurate work it is imperative that the bed 
should have no twist in it. Attention and care in this re- 
gard will increase the life of the lathe fifty per cent, also 
enabling it to turn out much more accurate and better 
work. 

Place the countershaft over the lathe, when necessary 



MACHINE TOOLS 333 

it can vary eighteen inches front or back of the center line. 
Have the hanger journals in line with the line shaft, and 
when the hangers are securely tightened, the countershaft 
should revolve freely. Place the thrust collars so that the 
shaft has one-eighth of an inch end play. The clutch pul- 
leys should have one-sixteenth of an inch end play on bush. 
Place the pulley for the slow speed to the left when stand- 
ing in front of, and facing, the lathe. Both driving pul- 
leys should run in the same direction. This will double 
the spindle speeds, also give a quick speed change for 
roughing and finishing work without shifting the belt. 

Clean the lathe carefully, and oil both the lathe and the 
countershaft thorougly. The countershaft pulley bushing 
can be oiled without throwing off the belt, and should be 
attended to at least once a month. The lathe should run 
thirty minutes under careful inspection to see that all parts 
are oiled and run properly. 

Automatic Feed Turret Lathe. The machine shown in 
Fig. 261 will take bar stock up to 3% inches in diameter 
which can be fed through the automatic chuck. The travel 
of the turret slide is 14 inches. The swing over the bed 
in 20 inches. 

The Head and Bed are cast in one piece, insuring the 
greatest strength and rigidity. The cone has three steps, is 
geared 1.85 to 1 and back-geared 7.44 to 1, the back gears 
being engaged and disengaged by friction clutches. 

The automatic chuck and the power roller feed handle 
bar stock of any shape. The chuck is operated by the 
long lever in front of the head, and the same lever also 
engages and disengages the roller feed. The chuck jaws are 
adjustable for any diameter from actual size to 1-16 inch 
smaller. One set of chuck jaws, and an outer stock sup- 
port, accompany the machine. 

The turret saddle is provided with a supplementary 
taper base, by means of which the center of the tool-holes 



334 



MACHINE SHOP PRACTICE 




MACHINE TOOLS 335 

in the turret can be adjusted to the exact height of the 
center of the spindle. Taper gibs, fitted the whole length 
of the saddle on each side, provide means of adjusting the 
slide sideways. The turret slide is equipped with a geared 
automatic feed, with four changes in either direction. 

The turret is hexagon in form, has six tool-holes 2V2 
inches in diameter, and also bolt holes for attaching tools 
to the faces. It is so arranged that stock of any diameter 
smaller than the tool-holes can pass entirely through. The 
index is nearly the full diameter of the turret, and the 
lock bolt is placed directly under the working tool. In- 
dependent adjustable stops are provided for each of the 
faces. 

The carriage has a geared automatic cross feed with four 
changes in either directions, and hand longitudinal feed. A 
tool post for holding forming and turning tools, and a 
cutting-off tool holder are provided. 

The geared feeds insure a positive drive, and any one of 
the changes is instantly available by moving a lever. The 
turret and carriage feeds are independent of each other and 
ooth are provided with adjustable automatic trips. 

The geared pump delivers a copious flow of oil to the 
cutting tools for both the turret and carriage, through 
two systems of piping. It operates when running in either 
direction. 

Back-Geared Lathe. In the lathe shown in Fig. 262 the 
spindle is made of 50 point carbon high grade crucible 
steel and runs in babbitt bearings. The bole in the spindle 
is 1 15-16 of one inch in diameter. The spindle nose is 
3^ inches in diameter, with 4 threads per inch. The front 
spindle bearing is 3% by 7 inches. The cone has 5 steps 
ranging from 5V 2 to 15 inches, for a 3-inch belt. The back 
gear ratio is Ll 1 /^ to 1. 

The headstock is massive, double-webbed its entire length, 
and not weakened to make room for the reverse plate. Am- 



336 



MACHINE SHOP PRACTICE 




MACHINE TOOLS 337 

pie oiling facilities are provided and oil-boles have dust- 
proof covers. The front end of the tailstock barrel is re- 
enforced to withstand heavy strains, it has a Xo. 4 Morse 
taper in a spindle, and the set-over is graduated. 

The apron is arranged so that it is impossible to throw 
in the rod and screw-feed at the same time. The rack- 
pinion can be thrown out of mesh with the rack, so that 
when chasing there is no resistance or friction of any mov- 
ing part in the apron. All the feeds are reversed in the 
apron. 

Threads can be cut from 2 to 24 per inch, including 11 y 2 
pipe thread. A chasing dial for catching the threads is 
provided, and threads can be cut without stopping the lathe 
or reversing the lead screw. 

The geared-feed is positive, all the feeds are obtained 
within the range of modern practice. There are also 3 belt 
feeds, ranging from .020 to .070 cuts per inch. 

The countershaft has double friction pulleys. 14 and 16 
in. diameter for a 4^ inch belt. Both belts should run 
forward as no backing belt is required. Speed of counter- 
shaft is 125 and 160 revolutions per minute. 

The lathe is made with either plain block or compound 
rest. A taper attachment, a turret on the shear, or a tur- 
ret on the carriage can be furnished if desired. 

Combination Turret Lathe. Figure 263 shows a 25-inch 
combination turret lathe. This is said to make an ideal 
manufacturer's lathe. It possesses all the quick speed and 
feed changes that are so important for the economical up- 
to-date production of work. "With the triple friction coun- 
tershaft nine changes of speed are obtained without shift- 
ing the belt. The head is geared 16 to 1, so that it has 
enormous power for facing and scaling cuts. 

The cone is arranged for a 4-inch belt, the smallest step 
is 12 inches diameter, thus securing at all times a good 
belt speed. This power is increased by a double friction 



338 



MACHINE SHOP PRACTICE 




MACHINE TOOLS 33^ 

back gear. The feeds are positive, four quick changes 
being made by a lever, these can be varied by change 
gears to suit all classes of work. The turret and car- 
riage feeds are independent of each other so that the cor- 
rect feed can be used on a boring and turning operation at 
the same time. The turret can also be connected to the car- 
riage and a feed obtained with the lead screw for a posi- 
tive lead in tapping. The carriage is furnished with our 
turret tool post, carrying four independent tools. 

Bench Lathe. For small or fine work the bench lathe 




Fig. 264. 

shown in Fig. 264 will be found a very useful adjunct even 
to a well equipped machine shop. 

Double Headed Manufacturer's Lathe. The lathe shown 
in Fig. 265 was designed for finishing work held by a face 
plate or chuck. Tail stocks can be furnished for work 
which requires centers. It is especially adapted for manu- 
facturing a large number of duplicate parts as it enables 
one operator to run two spindles. It is furnished with an 
automatic longitudinal and cross feed, the speeds and feeds 
for each head being independent. All feeds are reversed 
in the apron and are driven by a belt, the belt being kept 
at proper tension by belt tighteners. 



UQ 



MACHINE SHOP PRACTICE 




MACHINE TOOLS 



341 



Fourteen-Inch Lathe. A fourteen-inch lathe is shown in 
Fig. 266. The spindle is made from a crucible steel forg- 
ing and has a 15-16 inch hole through it. The cone pulley 
has five sections, the largest of which is 9^4 inches dia- 
meter for a 2 inch belt. The spindle bearings in the head 
stock are of cast iron lined with genuine babbitt metal. 




Fig. 266. 

It is furnished with an elevating rest, or with a plain 
rest. It can be furnished with a compound rest also taper 
attachment is furnished when wanted with either style of 
rest. 

Power cross feed is furnished with either style of rest. 
Independent rod and patent friction feed. Combined gear 
and belt feeds are furnished, also automatic stop motion 



342 MACHINE SHOP PRACTICE 

in connection with either gear or belt feed. The lathe is 
so arranged that the lower feed cone can be swung around 
to tighten the feed belt, at the convenience of the operator. 
There are six belt feeds ranging from 40 to 140 inclusive. 
When the geared feed is wanted the belt can be removed 
and the feed rod connected with the intermediate gear, 
then by changing the gears on the feed stud of the head 
stock, feeds can be obtained from 13 to 150, inclusive. 

It has a steel rack and pinion for moving the carriage. 
The back gear can be drawn out of the rack, thus pre- 
venting wear on these parts when not required in screw 
cutting and other similar work. The steel leading screw 
is of 5 pitch, with open and shut nut. It cuts threads 3, 4, 
5, 6, 7, 8, 9, 10, 11, liy 2 , 12, 13, 14, 15, 16, 18, 20, 22, 
24, 26, 28, 30, 32 and 36 per inch. 

The countershaft is furnished with friction pulleys 10 
inches diameter for 2y 2 inch belt, and should make 150 rev- 
olutions per minute. The pulleys can be oiled while run- 
ning, thereby saving loss of time, danger and annoyance in 
running off the belts, which is an important item where a 
number of lathes are in use. The countershaft has self 
oiling hangers. 

Motor-Driven Lathe. The claims made for a direct 
electric motor drive are : Greater efficiency of the tool ow- 
ing to a more powerful drive and correct cutting speed— 
doing away with the line shaft, countershafts, belts, etc., 
thus avoiding the dirt and grime which always follows the 
belt and darkens the shop— the facility for placing the tools, 
not having to depend on any special location for the drive 
—the elasticity of the whole arrangement for adding new 
tools, properly grouping them and changing when neces- 
sary. Also the fact that when the machine is not in use 
no power is being consumed, but the tools are always ready 
for work in case of an emergency or overtime without 
running a long line of shafting and countershafts. 



MACHINE TOOLS 



343 



A variable speed motor, with an electrical speed range 
of about three to one as shown in Fig. 267 is used. Whether 
this variable speed is obtained by multiple voltage or field 




control, the results prove satisfactory. This range is then 
multiplied mechanically to suit the tool. 



344 MACHINE SHOP PRACTICE 

The multiple voltage is based on well known principles; 
two or more different voltages are supplied to the armature 
of the motor from which speeds proportional to these vol- 
tages result. These speeds are then divided by field regu- 
lation giving the greatest range of any system. With the 
field control motor one voltage only is required, the entire 
speed range being obtained by changing the field. This 
form of control can therefore be used where power is ob- 
tained from an outside source, or when only one voltage is 
available. Where multiple voltage is used special arrange- 
ments are necessary in the power plant to obtain two or 
more voltages. 

With the belt drive it has been thoroughly demonstrated 
that from 45 to 75 per cent of the entire power generated 
is used by the transmission machinery, in very few in- 
stances is there more than 45 per cent used by the machine 
tool. With direct motor drive, from 70 to 80 per cent of 
the power generated is delivered at the machine. With any 
standard make of motor a range of speed changes can be 
obtained, increasing at a rate of about 10 per cent, while 
with the cone pulley, as at present used on most lathes, the 
increase ranges from 30 to 50 per cent. Having the proper 
speed for the work will therefore greatly increase the 
capacity of the tool. 

Motor-Driven Turret Lathe. The drawing shown in Fig. 
268 shows a 21-inch Turret Lathe arranged for a motor 
drive with field control. The motor has a speed range of 
3 to 1, the power bsing transmitted from the motor spin- 
dle to the gear quill with a silent chain, the field control 
giving 14 speed changes. These speeds can be transferred 
direct to the spindle by the lever shown on the friction 
head, or multiplied twice by the second lever which con- 
trols the double friction back-gear, giving 3 mechanical 
changes, and a total number of 42 spindle speeds, ranging 
from 8 to 382. This lathe can be stopped independently of 
the motor. 



MACHINE TOOLS 



345 




346 



MACHINE £HOP PRACTICE 



Pattern Maker's Lathu The lathe shown in Fig. 269 is 
carefully fitted up the ssame as an iron-working machine. 
It has adjustable bearing's, iron stop cone, carriage with 
rack and pinion movement, and cross carriage operated by 
a screw and handle. Automatic feeds can be supplied to 
the carriage when desired. 

The head spindle extends through the outer end of the 
headstock, and is provided with a large face plate for 
turning work larger than the swing of the lathe. On the 
larger sizes the head swivels for obtaining the draft on pat- 
terns. 




Pig. 269. 

The countershaft is equipped with friction clutch pulleys, 
one large and one quite small, giving a large range of 
speeds. The lathe is carefully balanced so that it will 
run at very high speeds without vibration. 

Plain Turret Lathe. The 16-inch turret lathe shown 
in Fig. 270 is designed to perform the simpler operations 
of chucking. For all work which does not require a car- 
riage or secondary tool on the slide, it will be found very 
useful. The turret is strong enough to carry heavy fac- 
ing tools, the spindles are heavy and provided with a large 



MACHINE r f<*>LS 



347 




348 MACHINE SHOP PRACTICE 

hole so that bar work can be conveniently handled, the end 
thrust is taken with ball bearings. The turrets are auto- 
matic and are made with or without power feed. The lathe 
can be made with back gears, also with double friction 
back gears and friction head. 

The front end of the spindle is bored taper to carry a 
bushing for supporting boring bars. The turret is of stand- 
ard make, all parts subject to wear being provided with 
adjustment to compensate for the same. The turret block 
is fitted with a taper bushing, so that it can always be kept 
tight on stem. The locking pin and ring are made of tool 
steel, hardened and ground, the locking pin has a bearing 
in the slide on both sides of the ring, the ring is placed 
at the extreme outside of the turret, so that the tool is 
rigidly supported. 

Quick Change Gear Lathe. The lathe shown in Fig, 271 
represents a quick change gear lathe, which are made from 
12 to 30-inch swing. These lalhes were designed to supply 
the demand for a tool on which a great variety of work 
could be done and which required continual changing. The 
quick feed changes are obtained in the simplest possible 
manner and so that there will be no undue friction. The 
device contains the minimum amount of parts, thus requir- 
ing the least amount of care and assures long life to the 
lathe. 

The gear change feed box is provided with ample oiling 
facilities, the bearings are of proportions, and the entire 
range of feeds can be obtained without stopping the lathe 
or removing a single gear. 

The special features of this quick change lathe are: 

There are no splined shafts, nor gears with key-ways, 
sliding or running on the shaft. 

Neither the hear nor bed is weakened by slots cast or 
cut in them. 

There are no shafts in torsion, the power being trans- 



MACHINE TOOLS 



349 




350 MACHINE SHOP PRACTICE 

mitted entirely by the gears, the shafts simply act as bear- 
ings and are not used for transmission. 

The locking pin is arranged so it does not over-hang but 
connects the sleeve directly to the case, and when addi- 
tional friction is necessary, the whole can be locked to- 
gether. 

The gear box is made so that it is impossible to mesh the 
gears on the corners, in other words the gears cannot be 
thrown into mesh until exactly in the proper position 
longitudinally. 

The handle at the bottom which, when placed in a central 
position, allows the feed works from that point to remain 
idle, so the gears can be changed at the highest speed 
without injury, the lower handle can then be thrown which 
connect the feed works to the gear box. 

The box is designed so that the speed of the feed gears 
is inversely proportioned to the threads to be cut, it being 
no harder on the gear box to chase four than forty threads 
per inch. 

No compound gearing used between the spindle and the 
feed box, loss of power, excessive strain and friction gen- 
erated by compound gears used in other devices of this 
kind is thus avoided. 

The gears are exceedingly strong with wide face and 
heavy pitch, and those which mesh by throwing them in on 
the teeth, are of steel. 

This lathe is made with an independent feed rod, so that 
splining the screw is not necessary and when the lathe is 
used for turning, the lead screw remains stationary. 

The gear box is so arranged that if necessary, any 
thread not on the index plate can be chased by using a 
change gear as on an ordinary lathe. 

All the feed works are easily accessible, no other part of 
the lathe has to be removed to get at them. 



MACHINE TOOLS 



351 




352 



MACHINE SHOP PRACTICE 




THE LATHE 353 

Quick Change Gear Engine Lathe. Fig. 272 shows an 
Instantaneous Change Gear Engine Lathe, with three step 
cone and double back gear, upon which forty changes of 
feeds and screw cutting may be obtained, without dupli- 
cation, as shown in the index. This lathe has reverse feed 
in the head for both feeds and screw cutting, also a re- 
verse in the apron for feed and power cross feed. The 
mechanism is so arranged that the longitudinal and cross 
feed cannot be engaged when cutting screws. 

Quick Change Gear 18-inch Lathe. Fig. 273 shows an 
18-inch Lathe, with instantaneous change gear device, with 
which forty changes of feeds and screw cutting may be 
obtained, without duplication. This lathe embodies all the 
well known features of standard lathes, having a reverse 
feed in the head for both feeds and screw cutting, also a 
reverse in the apron for feeds, the power cross feed is so 
arranged that cross feed and length feed may be operated 
at the same time. Provisions have been made so that 
longitudinal and cross feed cannot be engaged when cut- 
ting screws. 

Speed Lathe. The lathe shown in Fig. 274 is just the 
thing for manual training and technical schools, and is a 
simple, strong machine with many advantages. 

The bearings are self-oiling and dirt-proof. Dirt cannot 
possibly get to the spindle, even in the act of oiling every 
three months or so, as oil is put in below it. 

The advantage of this occasional oiling, and the assur- 
ance that lubrication is sufficient at all times, will be ap- 
preciated by those especially to whose care the machines 
are intrusted. 

The tailstock and tool-rest clamp rigidly by means of the 
levers on the front of the machine. 

Tool Maker's Lathe. The tool maker's lathe illustrated 
in Fig. 275 has the spindle made of 50 point carbon high 
grade crucible steel, and runs in boxes of lumen bronze. 



354 MACHINE SHOP PRACTICE 




Fig. 274. 

The hole in the spindle is eleven-sixteenths of an inch 
diameter. The spindle nose is 1^4 inches in diameter, with 
8 threads per inch. The front spindle bearing is 1 7-16 
by 2% inches. The cone has 3 steps ranging from 3 to 6 
inches in diameter for V/ 2 inch belt. The back gear ratio 
is 7y 2 to 1. 

The headstock is massive, double-webbed its entire length, 
and not weakened to make room for the reverse plate. 
Ample oiling facilities are provided, and oil-holes have 
dust-proof covers. 

The front end of the tailstock barrel is re-enforced to 
withstand heavy strains, and has a No. 2 Morse taper in 
spindle, and the set-over is graduated. 

The apron is arranged for screw and friction feed. The 
friction feed is through a worm and worm gear which run 
in oil. A power cross feed is provided. 



THE LATHE 



355 



Threads can be cut from 6 to 40 per inch, including 
ll 1 /^ pipe thread. 

The feed is positive and is reversed in the head. 

The countershaft has double friction pulleys, 6 inches 
in diameter for a 2-inch belt, and should run 160 and 220 
revolutions per minute. Foot power can be furnished if 
desired. 




Fig. 275. 

The .lathe is made with either plain block, compound, or 
rise and fall rest. 

Universal Turret Lathe. In all sizes of the machine 
shown in Fig. 276 the bed, pan and headstock are made in 
a single casting, thus greatly increasing rigidity, without 
corresponding increase of weight, and through this feature 
alone making greater accuracy possible by preventing any 



356 



MACHINE SHOP PRACTICE 




THE LATHE 357 

spring and movement of parts upon each other under 
strain. 

In these lathes the spindle construction has received spe- 
cial consideration, and in it have been incorporated refine- 
ments in the direction of accuracy heretofore used only in 
the highest grade of toolmakers' lathes and precision tools. 
The spindle is not only ground externally where it runs in 
bearings, but in the end of it is a hardened tool-steel liner 
forced into place, and after the spindle is mounted in its 
bearings, the nosepiece is ground internally and externally, 
the closer for the chuck jaws is also hardened and ground, 
as likewise are the chuck jaws or collets themselves, thus 
ensuring perfect concentricity of spindle and all parts car- 
ried by same. The removal of the nosepiece for the pur- 
pose of mounting a large chuck on the spindle does not in 
any way disturb the adjustment of the regular automatic 
chuck as it does in some other turret lathes. 

In the closing operation the immovability of the chuck 
is another characteristic and particularly valuable feature 
where second operations are required, as the stock is not 
moved lengthwise. This feature makes possible the ad- 
vantageous use of split step chucks, and these are the only 
turret lathes on which such attachments can be employed, 
aside from the bench or watchmakers' lathes on which tur- 
rets are sometimes employed where extreme accuracy in a 
turret machine is required. 

A very efficient power rod feed is used on these Turret 
Lathes, while on smaller machines an improved type of 
lever rod feed is employed. 

The power rod feed has many advantages. It does not 
mar the rod, as it handles squares and hexagons as easily 
as rounds, and has no delicate parts to get out of ad- 
justment. 

The illustration in Fig. 276 above shows the rod feed 
mechanism for the Turret Lathe. The carrier is not shown, 



358 MACHINE SHOP PRACTICE 

but one end of the steep pitch screw which traverses it can 
be seen at the left of the illustration. This screw is at- 
tached to a clutch placed between two gears which run in 
opposite directions. 

When the chuck-jaws are opened, the clutch is thrown 
in and the stock is traversed up to the stock-stop. The 
clutch is automatically thrown out by a very simple device: 
When the stock touches the stock-stop the carrier tends to 
pull the steep pitch screw away from the lathe and as this 
screw is attached to the clutch it pulls the clutch out of 
contact. A handle is provided for reversing the screw when 
it becomes necessary to run the carrier back for a new 
grip. 

The improved lever rod feed used on the turret lathes 
gives about double the feed of rod to a given movement 
of the lever than was formerly possible with this type of 
rod feed. 

The machines are furnished with a follower bar which 
enables short pieces of stock to be as conveniently handled 
as long bars and at the same time serves to keep such 
pieces concentric with the spindle. This arrangement is 
much preferable to tubes placed within the spindle foi 
roughly centering small and short pieces of bar, and feed- 
ing this crop end through by hand, or pushing it with a 
long bar. 

For gauging the length of stock delivered by the rod feed 
on the machines, an auxiliary stop is provided on the head- 
stock. This stop when not in use is swung upwards out 
the way of the operator and the turret tools. It is stiff 
and allows no chance for variation when once set to a 
given length. Fine adjustment for position of stop is made 
by a fitting at the outer end. 

On these machines the cross-slide is operated by lever 
with pinion and rack, and by screw with hand-wheel, the 
change from one to the other method being made in a 
moment by the operator. 



MACHINE TOOLS 



359 




Fig. 277. 



360 



MACHINE SHOP PRACTICE 



The Automatic Turret. The automatic Turret shown in 
Fig. 277 has as few parts as possible in its construction and 
can be fitted to any make of lathe from 12 inch to 30 inch 
swing. 

The turret block revolves automatically, and when the 
top slide is flush with the bottom it can be revolved by 
hand, and any tool can be rapidly brought in position for 
work. Wear between the turret block and stem is taken 
up by an adjustable taper bush. The indexing ring is of 
large diameter, made of tool steel hardened and ground, 
as is also the locking plunger, which takes a bearing on 
both sides of the locking ring. The locking plunger auto- 
matically adjusts itself for wear. The top slide is square- 
gibbed, and is adjusted with a taper gib. The turret is 
firmly clamped in any position on the bed by two eccentric 
clamps operated by a wrench from the front. 




Fig. 278. 

The power feed is positive, and is engaged by a lever at 
the front of the turret, and can be tripped to a line in 
any position by an adjustable stop. The feed belt on the 
smaller sizes can be made endless, as it is always kept at 
the proper tension by a swinging belt-tightener. The larger 



THE LATHE 



361 



sizes are driven by a silent chain, and means are provided 
for obtaining quick changes of feed through gears by a 
lever at the front of the lathe. 

Block Rest with Chasing Stop. 

Fig. 278 shows one of the plainest and most solid forms 
of rest, and for plain hard work there is nothing better. 
The tool post, rings and wedges are made of machinery 
steel and case-hardened. Adjustable taper gibs are used for 
taking up the wear on all sliding surfaces. 

Compound Rest. 

Fig. 279 shows a compound rest. The swivel is gradu- 
ated to 180 degrees and is invaluable for turning angular 
work or boring taper holes. The top slide screw is gradu- 




Fig 279. 



ated to thousandths of one inch for chasing. The tool post 
rings and wedges are made of machinery steel and case- 
hardened. Adjustable taper gibs are used for taking up 
the wear on all sliding surfaces. 

Full Swing Rest. The rest shown in Fig. 280 is to be 
clamped on the carriage, and, as the name implies, it can 
be used for turning the full swing c_? the lathe. It is also 



362 



MACHINE SHOP PRACTICE 



invaluable when used in connection with the regular rest. 
For instance, two steps of a cone pulley can be turned at 




Pig. 280. 

once by using" both rests at the same time. Two tools can 
also be used in roughing. 

Interchangeable Turret. Figure 281 shows an engine 
lathe fitted with a Turret on the Carriage. The combina- 
tion produces an excellent chucking lathe. They are accu- 




Pig. 281. 

rately and substantially made and will index to the one- 
thousandth part of an inch. The locking ring and pin 
are made of tool steel, hardened and ground. The locking 
pin has a bearing on both sides of the locking ring. The 



THE LATHE 



363 



center stud is tapering and fitted with a bushing so that 
all wear between the stud and taper can be adjusted. Tur- 
rets arranged in this way have all the feeds of the engine 
lathe, such as the power cross feed for scaling off work, 
the length and screw feeds for boring, reaming and tapping. 
They can be used for facing, and the larger sizes will han- 
dle box or forming tools to advantage. 

There is a substantial stop at the rear of the turret to 
always bring it to the correct central position. This can 
be turned out of the way when using the compound rest. 

Lathe Apron. The apron shown in Fig. 282 is of a 
geared type, doing away with worm and worm wheels. All 
the feeds are reversed in the apron, and arrangements are 




Fig. 282. 

made for dropping the rack pinion when chasing long 
screws. There is also a device for preventing the simul- 
taneous engagement of the rod and screw feeds. All gears 
in the apron are cut from the solid, the bevel gears and 
pinions are cut from steel. All the studs are hardened and 
ground. On the larger sizes a special bracket is used to 
support the rack pinion stud at its outer end. The longi- 
tudinal and cross feeds are both automatic. The cross 
feeds are graduated to the one-thousandth part of an inch. 



364 MACHINE SHOP PRACTICE 

Reverse Plate. The reverse plate on the lathe shown in 
Fig. 283 is located on the outside so that the head does 
not have to be cored. The gears can be easily oiled, and 
are always in position when required for cutting left hand 
threads. The change gears on both the stud and the lead 




Fig. 283. 
screw can be changed, and are so arranged that very few 
changes are required on the stud. On these lathes most 
threads can be chased by simply changing the gear on the 
lead screw. 

•Taper Attachment. Figure 284 shows a taper turning 
attachment with a compound rest. 

This taper attachment is strong and stiff, and attached to 
the rest complete in itself. It can be used at any desired 
place on the lathe, and is secured in position by simply 
tightening the screw shown on the arm attached to the bed. 



THE LATHE 



365 



Boring or turning to any desired taper can be accom- 
plished with this taper attachment, up to 3 inches to the 
foot, and it does not admit of lost motion. 

This taper attachment can be furnished with a lathe as 




Pig. 284. 

follows, with plain rest and power cross feed on any engine 
lathes from 12' to 30 inch swing, inclusive. 

With compound rest and power cross feed on any engine 
lathes from 12 to 30 inch swing, inclusive. 

With elevating rest and power cross feed on 14 and 15 
inch swing engine lathes. 

With elevating rest, 
but without power 
cross feed, on 12 inch 
swing engine lathes. 

With either plain 
rest or elevating rest 
on 14 or 16 inch stud 
and bolt lathes. 
Thread Chasing Dial. 
Some lathes are 
Fig. 285. furnished with a chas- 

ing dial as shown in Fig. 285 with which all threads can 
be cut without stopping the lathe or reversing the lead 




366 



MACHINE SHOP PRACTICE 



screw. No backing belt is required with this device, both 
belts can be run forward, giving a greater number of 
spindle speeds. With this chasing dial all even threads can 
be cut by engaging the lead screw with any line on the 
dial, all odd threads, such as 7, 9, 11, etc., on the long lines 
only. This little device is said to effect a saving of 33 
per cent in the time of chasing screws. 




Fig. 286. 



Three Tool Shafting Rest. The Three Tool Shafting 
Rest shown in Fig. 286 is made in two sizes for 24-inch 
and 30-inch lathes. It is arranged for flooding the work 
with water, and can be furnished with a pump if desired. 



THE LATHE 



36? 





Fig. 287. 





Fig. 288. 



Tool-Posts. Four styles of tool-posts are shown in Figs, 
287 and 288. The drawings show so clearly the construction 
that no further explanation is deemed necessary. 



368 MACHINE SHOP PRACTICE 

Cutting Speed and Feed of Lathe Tools. 

It will be observed that the cutting speed given in Table 
No. 17 for work of l 3 /^ inches diameter, is double that 
given as the most advantageous for work of 3 inches diam- 




Fig. 289. 

eter, while the feed or tool travel can be nearly the same 
in both cases. The reason of this is that the tool can be 
ground much keener for the smaller size work than it could 
be for the larger size work, and because the metal, being 




Fig. 290. 

cut off the smaller work, is not so well supported by the 
metal behind it as is the metal being cut off the larger 
work, and, in consequence, places less strain upon the tool 
point, as illustrated in Figs. 289 and 290. 



THE LATHE 



369 



Table No. 17 — Cutting Speeds and Feeds. 



STEEL. 





ROUGHING 


CUTS. 


FINISHING 


CUTS. 


Diameter of 
work in inches. 


Speed in Revs, 
per minute. 


Feed. 


Speed in Revs, 
per minute. 


Feed. 


1 and less 

1 to 2 

2 to 3 

3 to 6 


63 
57 
57 

48 


25 
25 
25 
20 


63 

57 
48 

48 


30 
30 
30 
30 



WROUGHT-IRON. 



1 and less 


112 


25 


121 


30 


1 to 2 


80 


20 


96 


30 


2 to 4 


80 


20 


80 


25 


4 to 6 


72 


20 


72 


25 


6 to 12 


63 


15 


72 


20 


12 to 20 


57 


12 


58 


16 



CAST-IRON. 



BRASS. 



COPPER. 



1 and less 


121 


20 


121 


20 


1 to 2 


112 


20 


112 


16 


2 to 4 


96 


20 


96 


10 


4 to 6 


80 


16 


80 


6 


6 to 12 


63 


14 


63 


6 


12 to 20 


63 


10 


63 


4 



1 and less 


380 


25 


380 


25 


1 to 2 


318 


25 


318 


25 


2 to 4 


255 


25 


255 


25 


4 to 6 


229 


25 


229 


25 


6 to 12 


191 


25 


191 


25 



1 and less 

2 to 5 
5 to 12 

12 to 20 



1114 
796 
637 

477 



25 
25 

25 

25 



1273 
954 
637 
477 



25 
25 
25 
30 



370 



MACHINE SHOP PRACTICE 



Cutting Tools for the Lathe. The angle of deflection of 
the point of a lathe tool will vary in its direction with 
relation to the work, according to the vertical distance of 




Fig. 291. 

the top of the tool-post from the horizontal center of the 
work. By reference to Figs. 291 and 292 it will be obvious 
that to produce work as nearly cylindrical as possible it is 
absolutely necessary, either to have the tool-post A as near 




/ 




Fig. 292. 

the work as possible, or else to have the top of the tool- 
post as short a vertical distance from the horizontal center 
line T of the work as can be had. The facing or side 



THE LATHE 



371 



tool shown in Fig. 293 mainly used for squaring up the 
ends of shafting or the sides of collars and washers. The 
point A of the cutting edge should be level with the cen- 

r 




Fig. 293. 

ter C which supports the work D and be set at an angle of 
about 30 degrees with the horizontal center line for 
Avrought iron and steel and level if used for brass or cast 
iron. 
If a lathe tool be supposed to be turning down or re- 



372 



MACHINE SHOP PRACTICE 



ducing the diameter of a piece of work in the direction of 
its length, the angle of clearance of the tool would be 
maintained under all conditions of work and rate of feed. 
But at each successive cut the angle of clearance of the 




J0*\ I 15 \ 



Fig. 294. 

tool will be changed and will continue to change as long 
as the work is being reduced in diameter. The only way 
therefore to obtain an equal clearance from the cut, would 
be to give the tool a different angle for each variation in 
diameter. Fig. 294 shows how much the shape of the tool 



THE LATHE 



373 




Fig. 295. 



374 



MACHINE SHOP PRACTICE 



would be affected by each variation in diameter. The tool 
in each position has a clearance of 5 degrees from the 
face of the work at the point A. In position 1 the tool 



Left-hand Side Tool.. 

Bight-hand Side Tool 

Bight-hand Bent Tool 

Bight-hand Diamond Point 
Left-hand Diamond Point 

Bound-nose Tool 

Cutting-off Tool 

Threading Tool 

Bent Threading Tool 

Bonghing Tool 

Boring Tool 

Inside Threading Tool 




Fig. 296. 

stands at 8^2 degrees with a right angle line drawn from 
the point A. In position 2 it stands at 10y 2 degrees and 
in position 3 at 15 degrees from the point A. A special 



THE LATHE 



375 



set of lathe tools are illustrated in Fig. 295 and their re- 
spective uses designated below: 

1— Left hand side cutting tool. 
2— Side tool for heavy roughing. 
3— Left hand side facing tool. 
4— Front cutting tool for brass. 
5— Right hand side tool for brass. 
6— Right hand tool for boring. 
7— Right hand tool for heavy boring. 
8— Round nosed tool for iron or steel. 
9— Cutting-off tool for small work. 
10— Deep cutting-off tool for large work. 

A standard or regular set of lathe tools is shown in Fig, 
296, the drawing is self explanatory. 




Fig. 297. 



A set of boring tools for lathe use are illustrated in 
Fig. 297, No. 1 is for taking a heavy cut in wrought iron. 
No. 2 for use on wrought iron when the work is so^oc 



376 MACHINE SHOP PRACTICE 

distance from the tool-post. No. 3 is to cut a square cor- 
ner at the bottom of a hole. No. 4 is to take a heavy cut 
in cast iron, while Nos. 5 and 6 are for boring in brass. 

Screw-Cutting. 

To determine the proper number of teeth in the change 
gears for screw-cutting in a Lathe. 

In a properly designed lathe, screws to any degree of 
pitch, or number of threads in a given length, may be cut 
by means of a leading screw of any given pitch, accom- 
panied with change gears and pinions as follows: 

Divide the number of threads in a given length of the 
screw which is to be cut, by the number of threads in the 
same length of the leading screw of the lathe. The quo- 
tient is the ratio that the gear on the end of the screw 
must bear to that on the end of the lathe spindle. 

Example: It is required to cut a screw with 5 threads 
in one inch, the leading screw being of y 2 inch pitch, or 
containing two threads in one inch. What must be the 
ratio of the gears to be used? 

Answer: 5-7-2=2.5, the ratio they must bear to each 
other. 

Then if a pinion of 40 teeth be upon the lathe spindle, 
40X2.5=100 teeth or the number required for the gear on 
the end of the lead screw. 

Screws of a greater degree of fineness than about 8 
threads in one inch, are more conveniently cut by an addi- 
tional gear and pinion, because the proper degree of 
velocity is more effectively attained thereby. These addi- 
tional gears on account of revolving upon a stud, are 
usually called the stud gear and pinion, but the method of 
calculation and ratio of screw are the same as in the pre- 
ceding example, and all that is further necessary is to de- 



THE LATHE 377 

cide upon any 3 gears, as those for the spindle and stud- 
gears, then multiply the number of teeth in the spindle- 
gear by the ratio of the screw, and by the number of teeth 
in that gear or pinion which is in contact with the gear 
on the end of the screw. Divide the product by the num- 
ber of teeth in the stud-gear in contact with the spindle- 
gear, and the quotient is the number of teeth required in 
the gear on the end of the leading screw. 

Example: A screw is required to be cut with 25 threads 
in one inch, the leading screw as before, having 2 threads 
in one inch. A gear of 60 teeth is used upon the end of 
the lathe spindle 20 teeth for the pinion in contact with 
the last screw gear, and 100 teeth for the pinion in contact 
with the gear on the end of the lathe spindle. Required 
the number of teeth in the gear for the end of the leading 
screw. 

Answer: 25-^2=12.5, and ( 60X12.5X20 )-KL00=150 
teeth. 

Or if the spindle and lead screw gear to be those fixed 
upon, or any one of the stud-gears to find the number of 
teeth in the other gear, then (60Xl2.5)-^-(150X100 )=20 
teeth, or (60X12.5X20) --100=100 teeth. 



378 



MACHINE SHOP PRACTICE 



Table No. 18 — Change Gears for Screw Cutting. The 


Leading Screw Being %-inch Pitch or 2 Threads 


per Inch of Screw. 


.3 

CD 

0) > 
U <D 
XJ ^ 
+3 O 

O o 
*-<X5 

(Do 

is 
1 


Number of 
teeth in 


a 

w 

"O . 

03 > 

si 

o o 

0) o 

s £ 


Number of teeth in 


-a . 

03 > 

So 
to 

o o 
s-xj 

O) o 
r& a 

II 
19 


Number of teeth in 


s 

a 

03 

& . 

+? 03 

h! bo 

80 


Fh 

o 

w 

cm 

a 

83 03 

a> a; 

1-3 bO 


a 
"S 
d) . 

03 <D 
Hi b0 


O 03 

03 a> 

a-S 

ol| 


a fcuo 

l! 

OS 

Sis 
20 


o 

bo 

a 

03 03 

h1 be 

60 


a; 
>3 

a 
"B 

i . 
h! bi 


«-a 

S bJD 
q a) 

si 

•s a 

t-t m 

03X3 


a tun 

11 

20 


<v 
u 
o 

DO 

bo 
P 

la 

h! bo 

100 


40 


81 


40 


55 


50 


95 


li 


80 


50 


81 


90 


85 


20 


90 


191 


80 


120 


20 


130 


1* 


80 


60 


81 


60 


70 


20 


75 


20 


60 


100 


20 


120 


1* 


80 


70 


91 


90 


90 


20 


95 


201 


40 


90 


20 


90 


2 


80 


80 


9* ^ 


60 


20 


65 


21 


80 


120 


20 


140 


2i 


80 


90 


10 


60 


75 


20 


80 


22 


60 


110 


20 


120 


21 


80 


100 


101 


50 


70 


20 


75 


221 


80 


120 


20 


150 


21 


80 


110 


11 


60 


55 


20 


120 


22| 


80 


130 


20 


140 


3 


80 


120 


12 


90 


90 


20 


120 


23| 


40 


95 


20 


100 


3i 


80 


130 


12| 


60 


85 


20 


90 


24 


65 


120 


20 


130 


31 


80 


140 


13 


90 


90 


20 


130 


25 


60 


100 


20 


150 


31 


80 


150 


131 


60 


90 


20 


90 


251 


30 


85 


20 


90 


4 


40 


80 


13| 


80 


100 


20 


110 


26 


70 


130 


20 


140 


4i 


40 


85 


14 


90 


90 


20 


140 


27 


40 


90 


20 


120 


41 


40 


90 


141 


60 


90 


20 


95 


27| 


40 


100 


20 


110 


4f 


40 


95 


15 


90 


90 


20 


150 


28 


75 


140 


20 


150 


5 


40 


100 


16 


60 


80 


20 


120 


281 


30 


90 


20 


95 


■«■ 


40 


110 


161 


80 


100 


20 


130 


30 


70 


140 


20 


150 


6 


40 


120 


161 


80 


110 


20 


120 


32 


30 


80 


20 


120 


«J 


40 


130 


17 


45 


85 


20 


90 


33 


40 


110 


20 


120 


7 


40 


140 


m 


80 


100 


20 


140 


34 


30 


85 


20 


120 


n 


40 


150 


18 


40 


60 


20 


120 


35 


60 


140 


20 


150 


8 


30 


120 


18| 


80 


100 


20 


150 


36 


30 


90 


20 


120 



The above table will suit a lathe with a leading screw 
of y± inch pitch, or 4 threads per inch, by doubling one 
of the driving gears or halving one of the driven gears. 



THE LATHE 379 

To find the angle or rate that must be given to the nose 
of the tool in a screw-cutting lathe, so as to cut a square- 
thread screw without injury to the sides of the threads. 

Draw a right angle triangle the base of which equals half 
the pitch of the screw to be cut, and the perpendicular 
equals the diameter of the screw minus the double depth 
of the thread. The hypothenuse of the triangle, drawn 
from the end of the base to the end of the perpendicular, 
gives the angle or rake for the tool from a vertical line 
with the bed of the lathe. 

Using the Center G-auge. The angles used on the gauges 
shown in Fig. 298 are 60 degrees for the U. S. Standard 
and Metric Gauges, and 55 degrees for the Whiteworth or 




Fig. 298. 

Stnglish Standard. The four divisions 14, 20, 24 and 32 
parts to the inch are useful in measuring the number of 
threads to the inch. The following parts to the inch can 
be determined by them, viz.: 2, 3, 4, 5, 6, 7, S, 10, 12, 14, 
16, 20, 24, 28 and 32. 

The table on the gauge is used for determining the size 
of tap drills for sharp 60 degree V threads and shows in 
thousandths of an inch the double depth of thread of tap 
aud screws of the pitches most commonly used. This table 
is made up by dividing 1.732', the double depth of thread 
of a screw that is one pitch, by the number of threads of 
the various pitches shown. For instance, the decimal .433 
represents the double depth of the thread of a screw that 
is 4 pitch, is obtained by dividing 1.732 by 4. In the same 
manner the double depth of thread of pitches not shown in 



380 MACHINE SHOP PRACTICE 

the table may be readily obtained. The double depth of 
thread of a screw that is 2 pitch, is one-half of 1.732. 

As the double depth of the thread represents the dif- 
ference in the diameter of a tap and a tap drill, to ob- 
tain the diameter of a tap drill of any desired pitch it is 
only necessary to subtract the decimal showing the double 
depth of the thread of that pitch from the diameter of the 
tap. For example, if the top is 4 pitch, is a sharp V 
thread, and one inch in diameter, subtract .433, the decimal 
showing the double depth of the thread of this pitch in 
the table, from 1 and the result, .567 of an inch, is the 
size of the tap drill, which would al'ow of a sharp thread 
in the hole. Allowance is to be made for the extent to 
which it is desired the threads should be flattened. 

The U. S. Standard Thread is flattened, top and bot- 
tom, 1-8 of its depth, so that the sizes of tap drills for 
this style of thread may be obtained by dividing the con- 
stant 1.299, which is 3 4 of the constant 1.732, by the pitch, 
and subtracting the result from the outside diameter. 

By the formulas given below, the results are the actual 
diameters at the botloms of the threads. The tap drills used 
is, in common practice, one that is one or two gauge num- 
bers larger, for the smaller, or numbered sizes, and one 
that is about .005 inches larger for the larger sizes. The 
amount allowed for clearance varies in different shops and 
on different classes of work. 

Formula for United States Standard. 

1.299 
Diameter of Tap Drill = Diameter of Tap — j^TT 

Sharp V Threads. 

Diameter of Tap Drill = Diameter of Tap — 

In Fig. 299 at A, is shown the manner of gauging ths 
angle to which a lathe centre should be turned. At B, 
the angle to which a screw thread cutting tool should be 



THE LATHE 



381 



ground, ana at C, the correctness of the angle of a screw 
thread already cut 

The shaft with the screw thread on it is supposed to be 
held between the centres of a lathe. By applying the 
Gauge as shown at D, or E, the thread tool can be set at 




Fig. 299. 

rignt angle : to the shaft and then fastened in place by the 
screw in the tool post, thereby avoiding any imperfect or 
leaning threads. 

At F and G, the manner of setting the tool for cutting 
inside threads is illustrated. 

Work done on the Turret Lathe. The parts shown in 
Pig. 300 are a few of the many that can be made on an 
automatic turret lathe, as shown in Fig. 276. 

In practice, all pieces are made from a continuous bar 
and are machined as follows: A long bar of iron or steel 
is pushed through the spindle, until the piece projects be- 
yond the chuck long enough to make the piece desired. 
The various tools on the turret are set for the different 
diameters and cuts, and after each performs its operation, 
it is turned out of the way to admit the next tool. Sine? 



382 MACHINE SHOP PRACTICE 



Fig. 300. 
a number of tools are set for the various diameters, it 
gives this machine a great advantage over the lathe where 
there is but one tool. 



MILLING MACHINES 383 



MILLING MACHINES. 

Erecting Milling Machines. Erect the miller on a good 
floor. It is essential that the floor be free from vibrations 
and stiff enough so that it will not give under the weight 
of the miller. Where possible a stone or concrete founda- 
tion will answer the purpose much better. 

When leveling use only solid packing under the base. 
Level in both directions, using an accurate level. See 
that the column rests securely on all corners. 

Place the countershaft directly over the miller. This is 
necessary in order to have the belt clear the overhanging 
arm support. Have the hanger journals in line with the 
line shaft. When the hangers are securely tightened the 
countershaft should revolve freely. Place the thrust col- 
lars so that the shaft has one-eighth inch end play. The 
on the bushing. This end play helps to distribute the oil. 
pulleys also should have one-sixteenth of an inch end play 
Place the pulley for the slow speeds next to the driving 
cone Both driving cones should run in the same direction, 
this will double the spindle speeds, it also will give a quick 
change without shifting the belt. 

The countershaft pulleys can be oiled without throwing 
off the belt, and should be oiled once a month. The hangers 
have self-oiling journals and the reservoir should be filled 
to tbe oil hole. The countershaft should be speeded ac- 
cordiag to the diagram so that an intermediate change of 
speed between the cone changes is had. This gives the best 
and greatest range. Care must be taken that the feed pulley 
runs in the direction shown by the arrow on feed box. 

Tc oil the machine observe the following rules:. Use 
good mineral oil. Fill the spindle oil chambers from the 



384 MACHINE SHOP PRACTICE 

oilers on the side of the column. All the oil holes are 
furnished with dust-proof oilers. In oiling the geared feed 
box place the speed change handle in the lowest hole, in 
this position the oil holes in the yoke can be readily filled 
from an oil can. The table saddle and gearing in the 
saddle are oiled through oil holes at the front of the 
saddle. Oilers are placed in all parts of the machine, 
showing very clearly where the oil is required. 

The machine and countershaft should be thoroughly 
cleaned and oiled and be let run thirty minutes under 
careful inspection to see that all the parts run properly. 

Adjusting Milling Machines. Locking the different move- 
ments of the machine does not interfere in any way with 
the gib adjustment, this adjustment being made entirely 
separate from the lock. All the parts are made so as to 
compensate for wear. To produce good work and a quan- 
tity of it it is imperative that the machine be kept in 
proper adjustment. 

The front journal of the spindle is made tapering, and 
the back journal straight. The thrust is taken at the front 
end of the spindle by a hardened steel and babbit collar. 
The wear on these collars will be in proportion to the wear 
on the spindle, and when adjusted back to fit the box will 
come to a proper bearing on the end thrust. 

To adjust the front journal, draw the spindle back into 
the box by tightening the nut. The nut is directly on the 
spindle and draws the spindle back into the box. There 
should be a space between the nut and the hub of the gear. 

To adjust the rear journal, tighten the nut, this draws 
the taper bronze bushing back into the column, compressing 
it on the spindle. The adjustment of the spindle will not 
interfere with the alignment of the machine. 

Care should be taken that the nut is securely fastened 
after adjustment. The table gib is made tapering, and is 
supplied with a tongue at the lower edge to keep it from 
lifting, it is adjusted longitudinally by screws which se- 



MILLING MACHINES 385 

eurely lock it for end movement. The gib being securely 
fastened cannot raise or move when the table is at the 
extreme position. By this method freer table movement 
is secured, avoiding' the cramp occasioned by the movement 
of the gib. To adjust the knee and saddle gibs tighten the 
large filister head screws. 

Locking the movements is entirely independent of the 
gib adjustment and is accomplished by the locking handle. 
In accurate work see that all movements not in use are 
securely locked, this greatly stiffens the machine. Place the 
cutter as close to the body of the machine as possible. Use 
the braces and supports on the overhanging arm for heavy 
work. Two supports are usually furnished. If the cutters 
are used at the extreme end of a long arbor see that both 
supports are used. The brace can be set at either side of the 
knee shoe, giving the maximum amount of cross movement 
when brace is used. It can be bolted to either of the arbor 
supports. 

To remove the spindle from the machine take off the 
nut carrying the arbor extracting rod, unscrew the inside 
nut, and this will force the spindle out. Care should be 
taken of the last two or three threads by tapping the end 
of the spindle with a piece of babbit or some soft metal 
so that the nut can be removed without forcing. When 
this nut is clear of the thread the spindle can be with- 
drawn from the machine. The nut must be raised to clear 
the spindle key. 

Use of Milling Machines. Oil is used in milling to ob- 
tain smoother work, and to make the milling cutters last 
longer, and, where the nature of the work requires, to 
wash the chips from the work or from the teeth of the 
cutters. It is generally used in milling a large number of 
pieces of steel, wrought iron, malleable iron or tough bronze. 
When only a few pieces are to be milled it frequently is 
not used, and some steel castings are milled without oil. 
In cutting cast iron oil is not used. For light, flat cuts it 



386 



MACHINE SHOP PRACTICE 



is put on the cutter with a brush, giving the work a thin 
covering like a varnish. For heavy cuts it should be led 
to the mill from the drip can, or it should be pumped upon 
or across the cutter in cutting deep grooves, in milling sev- 
eral grooves at one time, or in milling any work where, 
if the chips should stick, they might catch between the 
teeth and sides of the groove and scratch or bend the work. 
Generally lard oil is used in milling, but any animal or 
fish oils may be used. The oil may be separated from 
the chips by a centrifugal separator, or by the wet process, 




Fig. 301. 

so that a large amount may be used with but little waste. 

Some manufacturers prefer to mix mineral oil with lard- 
oil. 

There is a difference of opinion as to whether the work 
should be moved against the milling cutter as in Fig. 301. 
But in most cases experience shows it is best for the work 
to move against the milling cutter as shown. 

When it moves in this way the teeth of the cutter, in 
commencing their work, as soon as the hard surface or 
scale is one broken, arc immediately brought in contact 



MILLING MACHINES 387 

with the softer metal, and when the scale is reached it is 
pried or broken off. Also when a piece moves in this way, 
the cutter cannot dig into the work as il is liable to do 
when the bed is moved in the opposite direction. When a 
piece is on the side of a cutter that is moving downwards, 
the piece should, as a rule, have a rigid support and be fed 
by raising the knee of the machine. 

' Some work, however, is better milled by moving with the 
cutter. To drer« both sides of a thick piece with a pair of 
large straddle mills as shown in Fig. 302, it is better to 




Fig. 302. 

move the piece towards the left instead of the right as 
shown in Fig. 301, as the milling cutters then tend to keep 
it down in place instead of lifting it. 

Milling Machine. The following description in connection 
with the illustration shown at Fig. 303, will give the names 
of the prncipal parts of a milling machine and their use: 

A is the standard or column on which are attached the 
principal parts of the machine. 

B is the horn and carries the elevating screw which is 
used to raise and lower the table G. 

C is the screw spindle of the transverse or cross feed ad- 
justment for the table G. 

D is the screw spindle with a micrometer attachment for 
raising and lowering the table G. 



388 



MACHINE SHOP PRACTICE 



E is the crank-handle connected with the quick-return 
longitudinal movemeint of the table. 

F is the housing which carries the bearings of the step 
cone pulleys and the back-gear. 




Fig. 303. 

G is the table which carries the work. 
H is the overhanging arm, which is used to support the 
outer end of the horizontal spindle. 



MILLING MACHINES 389 

K is the universal dividing head with power feed. 

L is the foot-center or tail-stock. 

M is the lever for throwing the back-gears in and out of 
mesh. 

Automatic-feed Milling Machines. The journals of the 
machine shown in Fig. 304 are taper, self-oiling and self- 
adjusting, running in annular bearings, and capable of 
prolonged use without showing perceptible wear or need of 
alteration, and especially adapted to maintain true align- 
ment of the spindle. 

The front journal and thrust collar which runs loosely 
between the face of the bearing and spindle collar, 
are so proportioned in their combined bearing surfaces as 
to compensate each other for what wear may take place, 
and, as they are properly adjusted and tested before leav- 
ing the factory, will call for little or no attention outside 
of occasional renewal of oil supply in oil pockets. 

The rear journal is entirely independent of the spindle, 
and consists of a steel shell keyed to but sliding on the 
same. Its adjustments are independent of those of the 
front journal, and readily allow for contraction and ex- 
pansion of spindle under changes of temperatures. 

Large oil pockets are molded in either housing directly 
under the bearings, in which the oiling rings are suspended. 
These rings revolve with the spindle and cause a constant 
flow of oil to the bearings as long as the spindle revolves. 
The oil pockets should be filled until the oil shows in the 
oil hole covers at the side of the bearings. 

The driving cone has four steps, and with the back gears 
provides -eight changes of speed to the spindle, which may 
be doubled with the two-speed countershaft. The back 
gears are fully covered and protected. 

The upper housings carrying the overhanging arm are 
annular in form, the arm fitting the sleeves properly, 
clamping being effected by suitably shaped split bushings 
locked to the arm by means of the binding handles as 



390 MACHINE SHOP PRACTICE 

shown in the cuts. The use of the front binding handle 
alone is sufficient to hold the arm, as with binders loose 
there is no possibility of shake in either bearing. This we 
believe to be an important improvement over the common 
form of split shell for the housings, which when clamped 
is liable to disturb the alignment of the arm with the hole 
in the spindle. 

The overhanging arm is amply proportioned in each sized 
machine so as to rigidly support the outer end of the cut- 
ter arbor when under a heavy cut. The machines are all 
fitted with the straight bar and removable pendant, a desir- 
able feature where frequent changes to the vertical spindle 
or other attachments are necessary. All machines are fur- 
nished with the supporting braces to knee, as shown in cuts. 

The means for supporting the cutter arbors are as fol- 
lows: An adjustable center, small bronze collet, and large 
shell bushing, furnishing a variety of supports, suitable for 
each class of milling, whether it be light, medium, or heavy. 

All the machines have their center distances located and 
bored through the back-gear arms, overhead arm and spin- 
dle housings in a mill especially designed and constructed 
for this work. This mill supports and locates the body of 
the machine from its finished column, and insures accurate 
right-angled alignment of all holes with the column. 

The saddles and swivels are made liberal in size and 
weight, with long wings, giving extra length of bearing for 
the table, and increased support even when the table is 
used in its extreme positions. 

The swivel carriage for universal machines, carrying the 
table, is graduated in degrees through an arc on its front 
surface, and, the feed of the table being actuated from the 
center, it can be set and used at any angle up to 45 de- 
grees with the axis of the spindle. The carriage is firmly 
clamped to the saddle by means of three bolts working in 
T slots and links, placed well out from the center to afford 
the greatest rigidity. 



MILLING MACHINES 391 

The tables are very deep and rigid with bearings on the 
shoulders of the saddle or carriage instead of the foot of 
the angles. This method carries the support well out from 
the center and prevents any tendency of the table to rock 
when work is machined at or clear of the edge. The tables 
have oil ways, channels, and suitable T slots, and are fitted 
with draining cock. The tables furnished with plain ma- 
chines have a larger working capacity than those of the 
universals. The saddle and table are fitted with a taper gib 
having an adjusting screw at either end, making a positive 
lock for the gib when set. 

The elevating screws for knee are made telescope. This 
double construction greatly strengthens the screw, overcom- 
ing any tendency in single screws to buckle when the knee 
is at its highest elevation. The telescopic screw avoids the 
necessity of cutting through the floor as in the case of the 
ordinary type of single screw, to afford a means of escape 
when the knee is lowered to the capacity of the machine. 

Ball thrusts are fitted to the elevating screws, thus re- 
ducing the labor of operating the screws to a minimum, at 
the same time greatly increasing their sensitiveness to ad- 
justments. 

The binding handles are in use at all necessary points, 
superseding the old method of clamping with bolts and 
wrenches. 

Dividing Head and Center. These form part of the regu- 
lar equipment supplied with all universal machines, as 
illustrated in Fig. 304. The body of this head consists of 
a substantial base with parallel, annular housings, a center 
block carrying the spindle, worm gear and worm, and the 
trunnion supporting plates for the block. These trunnions 
have a 360 degree bearing of large diameter in their hous- 
ings, and are recessed into the block on either side, and 
permanently held in position when assembled with it by 
means of dowel. Binding bolts for clamping head when in 
position pass clear through the trunnion plates, one below, 



392 



MACHINE SHOP PRACTICE 



one above and one at the end of the spindle, which operate 
to bind the head in one compact whole with no deflecting 
strains of any kind set up in the head. The full circular 




Fig. 304. 

shape of the head affords means for a good length of 
spindle, which has taper journals at either end and an ad- 
justing collar at rear. 

Motor-Driven Milling Machines. Fig. 305 represents a 
Universal Milling Machine. This is a representative ma- 



MILLING MACHINES 



393 



chine, showing the general style and design of electrically 
driven millers. 

Experience has demonstrated that the most satisfactory 




Fig. 305. 

motor-driven milling machine is one driven by a variable 
speed motor with an electrical speed range of about three 
to one. This range being multiplied mechanically, gives the 
proper spindle speeds required. Whether the electrical vari- 



394 MACHINE SHOP PRACTICE 

ations are obtained by multiple or single voltage and field 
control, the results prove equally satisfactory. The mul- 
tiple voltage is based on well known principles, two or 
more different voltages are supplied to the armature of the 
motor from which speeds proportional to these voltages re- 
sult. These speeds are then divided by field regulation, 
giving the greatest range of any system. With the field con- 
trol motor one voltage only is required, the entire speed 
range being obtained by changing the field. This form of 
control can therefore be used where power is obtained from 
an outside source, or when only one voltage is available. 

The great advantage of an electrically driven machine is 
the fact that the speed range can be obtained by much 
smaller increments than it is possible to obtain a like range 
mechanically. The machine thus driven by a variable speed 
motor greatly increases the available number of spindle 
speeds and also simplifies the mechanical changes, and pro- 
cures for the operator the proper cutting speeds for all 
diameters of cutters. It is necessary with a variable speed 
motor to have mechanical changes in connection with the 
electrical, the steps or intervals of these mechanical changes 
are equal to the entire electrical speed range of the motor, 
thus securing changes of speed in geometric progression. 

The three mechanical changes required, are obtained by 
a quill on the spindle which takes the place of the ordi- 
nary cone. This quill being double back geared, gives one 
change when connected direct to the face gear and two 
more changes when back-geared. The drive from the motor 
shaft to the quill is by a noiseless chain through a friction 
pinion, so that the frequent operations of starting and stop- 
ping the machine to test the work or for any other purpose 
are entirely mechanical and are performed without any in- 
terference with the electrical details. With this arrange- 
ment all delay in stopping the rapidly running motor and 
the additional delay in again bringing up the speed is 
avoided— the operator cannot fail to start the machine 



MILLING MACHINES 395 

again at the previous speed. The mechanical changes are 
thus covered by the speed range of the motor, a complete 
range of spindle speeds being obtained in geometrical pro- 
gression with an average increase of not more than 3 per 
cent. 

Motor-Driven Universal Millers. The machine shown in 
Figs. 306 and 307 represents the most modern practice in 
milling machine design. It differs radically from the 

a & 




Fig. 306. 

standard machine in that it has a gear instead of a belt- 
cone on the main spindle for speed changes, giving a 
greater range of spindle speeds, and the full range of feeds 
is entirely independent of the spindle speeds. In this miller 
these results are accomplished in the following manner: 
What may be called the driving shaft carries the large 
flanged pulley on the outer end, and is driven either from 



396 



MACHINE SHOP PRACTICE 



ordinary countershaft or from motor, as shown in the cut. 
Sliding on this driving 1 shaft, inside the base or column is 
the regular form of bracket carrying the driving gear and 
intermediate, which may be meshed into any one of the 
six gears forming the cone on the spindle, and controlled 
by the guiding handle fitted with a spring latch, the two 




Fig. 307. 

engaging in the guiding slots and locking holes in the upper 
wall of the opening. Six different and progressive direct 
spindle speeds are thus available, and, as the machine is 
double back geared, a series of eighteen different and pro- 



MILLING MACHINES 397 

gressive spindle speeds is supplied, having- a rang of 16 to 
370 revolutions per minute. 

The back gearing may be left constant!} 7 in mesh if pre- 
ferred, and when so set up it facilitates handling the entire 
range of speeds, as by means of the two positive clutches, 
one of which is mounted direct on the spindle, the other on 
the back gear shaft, and both controlled by the two levers 
shown on the left side of the machine, one direct and two 
back gear speeds are handled for every setting made in the 
cone of gears on the spindle. 

All gearing entering into this combination, excepting the 
large face gear and large back gear, is made of steel. The 
clutches are made of crucible steel, and are hardened. 

The upper lever shown in Fig. 307, controls the out and 
in clutch for the back gear or direct drive, while the lower 
lever controls the fast and slow back gear combination. 

The hand wheel attached to the rear end of the spindle 
furnishes a convenient means for rolling the spindle over 
by hand, either for entering gears or close setting to work. 

The feed shaft is geared from the driving spindle with a 
chain and sprocket as shown in Fig. 308, and the whole 
eighteen feed changes are available for each and every 
spindle speed. 

The feed index plate gives the table travel in inches, 
running from % to 20 inches per minute. These speeds 
apply practically to saddle and knee feeds also, as both are 
automatic. 

The simple method of mounting the motor makes it possi- 
ble to use any standard make of reversible motor in place 
of a countershaft if so desired. 

Simple Indexing. The first office of the indexing head 
stock or dividing head, is to divide the periphery of a piece 
of work into a number of equal parts, and in connection 
with the foot stock, it also enables the milling machine to 
be used for work sometimes done on planer centres and on 
gear cutting machines. 



398 



MACHINE SHOP PRACTICE 




Pig. 308. 

As the index spindle may be revolved by the crank, and 
as in this case forty turns of the crank make one revolution 
ot the spindle, to find how many turns of the crank are 



MILLING MACHINES 



399 



necessary for a certain division of the work- or what is 
the same thing, for a certain division of a revolution of 
the spindle, forty is divided by the number of the divisions 
which are desired. The rule then, may be said to be, divide 
forty by the number of divisions to be made and the quo- 
tient will be the number of turns, or the part of a turn, 
of the crank, which will give each desired division. Apply- 
ing this rule— to make forty divisions the crank would be 
turned completely around once to obtain each division, or to 
obtain twenty divisions it would be turned twice. When, 
to obtain the necessary divisions, the crank has to be 
turned only a part of the way around, an index plate, 
shown in Fig. 309, is used. For example: If the work is 
to be divided into eighty divisions the crank must be 
turned one-half way around, and an index plate with an 
even num- 
ber of holes 
in one of 
the circles 
would b e 
selected, it 
being nec- 
essary only 
to have two 
holes oppo- 
site to each 
other in the 
plate. If 
the work is 
to be divid- 
ed into three 
divisions an 
index plate 
should be Fig. 309. 

selected which has a circle with a number of holes that can be 
divided by three, as fifteen is divisible by 3, five times. 




400 



MACHINE SHOP PRACTICE 







Table No. 19- 


-Index Table. 






V 
S 

o 

a. 2 

CO 
ft 


to ■ 

1 8 

ft 


as 

M 

00 

2 O 

ft 


S 


t-> . 

-2 a 

a. 2 

3 so 
ft 


S H 

ft 


03 

si 

ft 




2 


ANY 


20 


35 


49 


1 7-49 




3 


39 


13 '13-39 


36 


27 


1 3-27 




4 


ANY 


10 


37 


37 


1 3-37 




5 


<< 


8 


38 


19 


1 1-19 




6 


39 


6 26-39 


39 


39 


1 1-39 




7 


49 


5 35-49 


40 


ANY 


1 




8 


ANY 


5 


41 


41 


40-41 




9 


27 


4 12-27 


42 


21 


20-21 




10 


ANY 


2 


43 


43 


40-43 




11 


33 


3 21-33 


44 


33 


30-33 




12 


39 


3 13-39 


45 


27 


24-27 




13 


39 


3 3-39 


46 


23 


20-23 




14 


49 


2 42-49 


47 


47 


40-47 




15 


39 


2 26-39 


48 


18 


15-18 




16 


20 


2 10-20 


49 


49 


40-49 




17 


17 


2 6-17 


50 


20 


16-20 




18 


27 


2 6-27 


52 


39 


30-39 




19 


19 


2 2-19 


54 


27 


30-27 




20 


■ ANY 


2 


55 


33 


24-33 




21 


21 


1 19-21 


56 


49 


35-49 




22 


33 


1 27-33 


58 • 


29 


20-29 




23 


23 


1 17-23 


60 


39 


26-39 




24 


39 


1 26-39 


62 


31 


20-31 




25 


20 


1 12-20 


64 


16 


10-16 




26 


39 


1 21-39 


65 


39 


24-39 




27 


27 


1 13-27 


66 


33 


20-33 




28 


49 


1 21-49 


68 


17 


10-17 




29 


29 


1 11-29 


70 


49 


28-49 




30 


39 


1 13-39 


72 


27 


15-27 




31 


31 


1 9-31 


74 


> 37 


20-37 




32 


20 


1 5-20 


75 


15 


8-15 




33 


33 


1 7.33 


76 


19 


10-19 




34 


17 


1 3-17 


78 


39 


20-39 



MACHINE TOOLS 



401 



Table No. 19 (Continued) — Index Table. 


3 
o 

u . 

& a 

5.2 
3 "3 


£"2 

2* • 

2 M 


03 

E * 


"c 

Is 

go 

5 '55 


'{- x 
CO 

E£ 

o 

,0.-** o 

1st 


w 

1-3 


80 


20 


10-20 


164 


41 


10-41 


82 


41 


20-41 


165 


33 


8-33 


84 


21 


10-21 


168 


21 


5-21 


85 


17 


8-17 


170 


17 


4-17 


86 


43 


20-43 


172 


43 


10-43 


88 


33 


15-33 


180 


27 


6-27 


90 


27 


12-27 


184 


23 


5-23 


92 


23 


10-23 


185 


37 


8-37 


94 


47 


20-47 


188 


47 


10-47 


95 


19 


8-19 


190 


19 


4-19 


98 


49 


20-49 


195 


39 


8-39 


100 


20 


8-20 


196 


49 


10-49 


104 


39 


15-39 


200 


20 


4-20 


105 


21 


8-21 


205 


41 


8-41 


108 


27 


10-27 


210 


21 


4-21 


110 


33 


12-33 


215 


43 


8-43 


115 


23 


8-23 


216 


27 


5-27 


116 


29 


10-29 


220 


33 


6-33 


120 


39 


13-39 


230 


23 


4-23 


124 


31 


10-31 


232 


29 


5-29 


128 


16 


5-16 


235 


47 


8-47 


130 


39 


12-39 


240 


18 


3-18- 


132 


33 


10-33 


245 


49 


8-49 


135 


27 


8-27 


248 


31 


5-31 


136 


17 


5-17 


260 


39 


6-39 


140 


49 


14-49 


264 


33 


5-33 


144 


18 


5-18 


270 


27 


4-27 


145 


29 


8-29 


280 


49 


7-49 


148 


37 


10-37 


290 


29 


4-29 


150 


15 


4-15 


296 


37 


5-37 


152 


19 


5-19 


300 


15 


2-15 


155 


31 


8-31 


310 


31 


4-31 


156 


39 


10-39 


312 


39 


5-39 


160 


20 


5-20 


360 


18 


2-18 



402 



MACHINE SHOP PRACTICE 



Compound Indexing. To illustrate the manner of using 
the machine shown in Fig. 310 in compound indexing, sup- 
pose that it is desired to divide the work into 69 parts. 
Reference to Table No. 19 shows that the work is moved 
through 21 spaces, or holes in the 23 hole circle and then 
turned in the opposite direction 11 holes in the 33 hole cir- 
cle of the index plate shown in Fig. 310. The first move- 
ment is made in the ordinary manner. The stop or back 
pin is placed in the 33 hole circle, the index-crank pin is 




Fig. 310. 

pulled out of the 23 hole circle, and the index crank is 
turned through 21 holes in the desired direction, the holes 
being measured by the sector. For the second movement, 
the index crank pin is left in the 23 hole circle, the back 
pin is pulled back from the plate, and as the minus sign 
is given in the table, the crank is turned 11 holes in the 
direction opposite to that of the former movement. In 
this part of the indexing the index plate and crank turn 
together, and as there is no sector on the back of the plate, 
the holes or spaces have to be counted directly in the plate. 
Had the plus sign been given, as in the indexing to obtain 
77 divisions of the work, both movements of the crank 
would have been in the same direction. Ordinarily the 
order of the movements is not material and if more con- 



MACHINE TOOLS 



403 



venient for any reason, the back pin could usually be with- 
drawn first, and the movement described as the second 
could be made first. In some instances as in dividing the 
work into 174, 272 or 273 parts, the outer circle is natur- 
ally used first. 

To obtain 77 divisions the figures are A + A = f + tt = 
f f "J" tt == tf = one division. 

The table gives the movements for absolute divisions of 
the work of nearly all numbers from 50 to 250. 





Table No, 


19 — Compound Index Table. 


No. of 
Teeth. 


Index Moves. 


^No^f 
Teeth. 


Index Moves. 


No. of 
Teeth. 


Index Moves. 


50 


16-20 


94 


20-47 


160 


5-20 


52 


30-39 


95 


8-19 


164 


10-41 


54 


20-27 


96 


3-18 + 1-24 


165 


8-33 


55 


24-33 


98 


20-49 


168 


5-21 


56 


35-49 


99 


15-27 — 5-33 


170 


4-17 


58 


20-29 


100 


8-20 


172 


10-43 


60 


26-39 


104 


15-39 


174 


11-33 — 3-29 


62 


20-31 


105 


8-21 


180 


6-27 


64 


10-16 


108 


10-27 


182 


3-39 + 7-49 


65 


24-39 


110 


12-33 


184 


5-23 


66 


20-33 


115 


8-23 


185 


8-37 


68 


10-17 


116 


10-29 


186 


17-31 — 11-33 


69 


21-23 — 11-33 


120 


13-39 


188 


10-47 


70 


28-49 


124 


10-31 


190 


4-19 


72 


15-27 


128 


5-16 


195 


8-39 


74 


20-37 


130 


12-39 


196 


10-49 


75 


8-15 


132 


10-33 


198 


3-27 + 3-33 


76 


10-19 


135 


8-27 


200 


4-20 


77 


9-21 + 3-33 


136 


5-17 


205 


8-41 


78 


20-39 


138 


11-33 — 1-23 


210 


4-21 


80 


10-20 


140 


14-49 


215 


8-43 


82 


20-41 


144 


5-18 


216 


5-27 


84 


10-21 


145 


8-29 


220 


6-33 


85 


8-17 


147 


13-39 — 3-49 


225 


5-18 — 2-20 


86 


20-43 


148 


10-37 


230 


4-23 


87 


23-29- 11-33 


150 


4-15 


231 


3-21 + 1-33 


88 


15-33 


152 


5-19 


232 


5-29 


90 


12-27 


154 


8-21 — 4-33 


235 


8-47 


91 


6-39 + 1-4 


155 


8-31 


240 


3-18 


92 


10-23 


156 


10-39 


245 
| 248 


8-49 


93 


3-31 + 1-3 






5-31 



404 



MACHINE SHOP PRACTICE 



Cam Cutting Attachment. The attachment shown in Fig. 
311 is used for cutting" either face or cylindrical cams from 
a flat former cut from a disk. 




All the necessary movements are contained in the attach- 
ment itself, thereby allowing- the table of the machine to 



MACHINE TOOLS 405 

remain clamped in one position during the cutting of the 
cam. 

Cams 12 inches in diameter can be cut with any throw 
up to 5 inches. 




Fig. 313. 

Circular Milling Attachment. The attachment shown in 
Fig. 312 is new in design and is well adapted for use upon 
milling machines in connection with a vertical spindle 
millino- attachment. 



406 



MACHINE SHOP PRACTICE 



The Table is 18 inches in diameter and has 4 T slots % 
inches wide. The circumference of the entire circle is 
graduated to degrees. 

The Feed of the table is operated by the hand wheel 
shown in the drawing. The worm can be thrown out of 
mesh and the table easily turned by hand. 

A clamp screw is provided for clamping the table in 
position. 

Cutter Grinding Attachment. The attachment illustrated 
in Fig. 313 is used for grinding the teeth of formed cutters 




Fig. 314. 



radially, this being necessary in order to insure their cut- 
ting the correct form. It consists of a bed rigidly attached 
to the main bar, that carries a sliding table provided with 



MACHINE TOOLS 



407 




Pig. 315. 
a pair of index centers, between which the work to be 
ground is held. 

The Centres swing 4 3-4 inches in diameter and take 10 
1-2 inches in length. 

The Index Plate has 24 holes and can be turned by a 
worm or the worm can be disengaged and the plate turned 
by hand. 

Formed Cutters to 8 inches in diameter can be ground by 
the use of raising blocks. 



408 MACHINE SHOP PRACTICE 

Hight Speed Milling Attachment. A high speed milling 
attachment is shown in Fig. 314. By means of an internal 
gearing and a pinion it is geared up about 3 to 1. 

Lincoln Milling Machine. This machine (Fig.315) is radi- 
cally different in construction to that of those in general 
use. The spindle is raised and lowered and the carriage 
has only two movements, longitudinal and transverse. 

Geared Pump. The pump shown in Fig. 316 is princi- 
pally used on machines where the cutting tools operate 




r lg. 3xo. 



only in one direction, as milling machines, gear cutting 
machines, chucking machines. But, by running the pump 
independently, it can be used on machines that reverse. 

It is simple in construction, the principal mechanism be- 
ing a pair of gears which run together in a tight case. 

To obtain the best results the pump should be placed as 
near as possible to the level of the liquid in the tank. 

Gear Catting Attachment. The spindle of the machine 
shown in Fig. 317 is 2% inches in diameter, and is made 



MACHINE TOOLS 



409 



tapering to compensate for wear. The master wheel is 7 
inches in diameter with 40 divisions. With the small lever 
on the side the spindle can be securely locked in any posi- 
tion, relieving the index pin from all strain. The worm 




Fig. 317. 



shaft can be adjusted to compensate for wear, and when 
necessary can be instantly thrown out of mesh and the 
divisions had with the notched wheel at the rear. This is 
very convenient for quick divisons. The spindle is hollow 



410 



MACHINE SHOP PRACTICE 



and bored to No. 10 B. & S. taper. Tail stock is adjustable 
for taper work. With index plates furnished all numbers 
to 50, the even numbers to 100, and most numbers to 366, 
can be divided. The tail stock is adjustable, the adjust- 
ments being- obtained by a screw so that it can be set rnv 
curately and securely clamped in position. 




Fig. 318. 

Hand Milling Attachment. A plain Milling Machine 
with a Rack Feed can be quickly changed by means of the 
attachment shown in Fig. 318 into a hand milling machine 
with or without an automatic longitudinal feed. 

An apron, placed on the outside end of the knee, carries 
a lever attached to a segment of a gear which runs in a 
pinion placed over the end of the shaft that moves the 
table longitudinally, and this lever when moved turns the 
shaft as the crank would if it were in position. 



MACHINE TOOLS 



411 



The attachment, with a knee, is clamped on the table and 
on this the fixtures for holding the work can be fastened 
as on a hand milling- machine. When brought to position 
the lever can be held b}- the clutch in the holder, shown 
at the left of the drawing, which can be released by a 
latch on the back of the lever, so that at the same time 
that the knee is returned to position the catch is released 
without an extra movement. While the lever is held down, 
the feed can be thrown in and milling done as on a plain 
milling machine. 




Fig. 319. 

Plain Vise. The vise illustrated in Fig. 319 is provided 
with flanges for clamping them to the table of milling or 
planing machines, they are a very convenient and ex- 
tremely useful tool. 

Quill Gear Cutting Attachment. The attachment shown 
in Fig, 320 is for cutting the small members of quill gears, 
as shown in the drawing, or other gears of similar con- 
struction. 

They are easily and quickly placed in position or re- 
moved. 

The cutter spindle is raised above the cutter spindle of 
the machine and driven by a train or gears. 



412 



MACHINE SHOP PRACTICE 




Fig. 320. 

Rack Cutting Attachment. The attachment shown in 
Fig. 321 embodies in its construction many important im- 
provements that greatly enhance its value, making, it ex- 
ceptionally rigid and convenient. All working parts are 
entirely enclosed, thus protecting them from dirt and chips. 

The upper part of the frame is clamped to the over- 
hanging arm, means being provided for vertical adjust- 
ment to compensate for any variation in the center dis- 
tance between arm and spindle. The lower part of the 
frame is clamped to the front of the knee slide, and pro- 
vided with means for adjusting the cutter spindle parallel 
with the table. 

The cutter spindle is hardened and ground, and runs in 
phosphor bronze boxes. The front box is provided with 
means of compensation for wear. It is smoothly and pow- 
erfully driven by the main spindle of the machine, through 
spiral and herring bone gears. 

Rack Cutting Attachment. The body of the attachment 
shown in Fig. 322 and its supporting bracket which clamps 



MACHINE TOOLS 



413 



to the column of the machine are formed, of one casting, 
making it very rigid. The front pendant forms the cap 
for the head of the attachment to which it is firmly screw- 
ed and doweled. All the gearing is made of steel. The 




152!^^ 




Fig. 321. 



shafts run in bronze bearings, and the cutter arbor has 
taper journal at its head end. The movable jaw of the 
vise is made of steel. 
Universal v Plain Millers. The Universal Miller shown 



114 



MACHINE SHOP PRACTICE 




Fig. 322. 



in Fig. 323 is exactly the same as the Plain Miller shown 
in Pig. 324 except that provisions are made for swiveling 
the table and automatically rotating the universal head. 
They are especially useful in tool rooms, or where there is 
a large variety of work. They can perform every opera- 
tion of which a Plain Miller is capable, having, in addition 
to the parts of the Plain Miller the swivelling table and 
universal head with the means for rotating the head, giv- 
ing facilities for cutting spirals, notching worm wheels, etc. 
Universal machines are not as good as Plain Millers for 
manufacturing purposes. The swiveling feature makes one 
more joint, and also lessens the vertical range. The feeding 
mechanism has to be brought up through the center of the 
swivel, thus restricting the design, and consequently they 
can not be made as simple and substantial as a Plain Mil- 



MACHIiNE TOOLS 



115 



ler. However, these are the faults of the type and not of 
the machine. 
Plain Milling Machine. The spindle of the machine 




Fig. 323. 



shown in Fig. 325 is crucible steel and the bearings ground. 
The bronze boxes provided with means of compensation 
for wear. The spindle is driven from the cone by a gear 



416 MACHINE SHOP PRACTICE 

and . pinion. The vertical adjustment by means of nuts 
on a vertical screw. 

The overhanging arm is of solid steel. 

Feed. Longitudinal, automatic, 15 inches. Can he au- 
tomatically released at any point. Four changes, varying 
from .015 inch to .066 inch to one revolution of spindle. 




Pig. 324. 



Oil Tank. Provides for use of pump. 
Vise. Flanged. Jaws hardened, Qy 8 inches wide, 1 9-16 
inch deep, open 3% inches. 



MACHINE TOOLS 



m 



Bench Milling Machine. A small bench hand miller is 
illustrated at Fig. 326, it has both vertical and horizontal 
spindles, and raising and lowering table with cross and 




Pig. 325. 

longitudinal feeds, operated by hand levers. This will 
be found an extremely useful tool for milling key-wayu, 
making small tools, etc. 



413 



MACHINE SHOP PRACTICE 




Fig. 326. 

Vertical Spindle Milling Machine. The spindle of the 
machine shown in Fig. 327 is of crucible steel and the 
bearings ground, and with bronze boxes. The lower box 
is provided with means of compensation for wear. 

The feeds are positive. All the spur gears are driven 
by chain and have 20 changes, varying in geometrical pro- 
gression, from .0012 to .060 inches per revolution of the 
spindle. There are no loose change gears. The changes 
are made by an adjustment of the index slide and lever. 

Slotting Attachment. The attachment illustrated in Tig. 
328 is new in design and is particularly well adapted for 
tool making of all kinds, as in forming box tools for screw 
machines, making templates and work of a similar charac- 
ter. 

It is simple in construction, there being no auxiliary 
fixtures or belting required for attaching it to the ma- 



MACHINE TOOLS 



418 




chine. It is exceptionally rigid when in position, the upper 
part of the frame being clamped to the overhanging- ami, 
and the lower part of the top of the knee slide. 



420 



MACHINE SHOP PRACTICE 



The tool slide is driven from the main spindle of the 
machine by an adjustable crank that allows the stroke to 
be adjusted. The slide can be set at any angle, between 
to 10 degrees, on either side of the center line. The 
position being indicated by a scale on the lower part of 
the frame, 




Fig. 328. 

The tool holder allows for the use of tools with shanks 
y 2 inch in diameter. The tools are held in place by a clamp 
bolt and a tool stop that swings over the top of the tool 
shank and prevents any possibility of the tool being push- 
ed through. The holder is also provided with a key that 



MACHINE TOOLS 



421 



fits the key-ways in the shanks of the tools and insures 
their relative positions always being the same. 

When the attachment is in position both the longitudinal 
and transverse feeds of the machine are available and have 
dials that read to .001 of an inch. 




',.""-" 



Fig. 329. 

Swivel Vise. The vise shown in Fig. 329 is exceptional- 
ly rigid and convenient for milling or planing. These vises 
are exceptionally low and bring the work close to the table, 
thus insuring rigidity and compactness. 

Toolmaker's Universal Vise. The vise illustrated in Fig. 
330 is of an entirely neAv design, for use on milling ma- 
chines and is so constructed that it can be set at any angle 
to the surface of the table or to the spindle of the ma- 
chine, and rigidly clamped in position. 

The base is double, the upper portion is graduated, and 
can be set at any angle in a horizontal plane. On the top 
of the swivel base is a hinged knee, which can be set at 
any angle, to 90 degrees, in a vertical plane. The top of 
the knee is graduated. The knee is clamped rigidly in posi- 
tion by means of the nut on the end of the bolt forming 
the hinge, and the locking levers shown at the left of the 
cut. These levers are clamped in position by the bolt shown 
in the center and the bolts at the ends of the levers. 



422 



MACHINE SHOP PRACTICE 



The vise proper is fastened to the hinged knee in such a 
manner that it can be set at any angle on a horizontal 
plane, and can be clamped in position by the bolt which 
holds the upper locking lever. 




Fig. 330. 



The vise base is fastened to the table by means of two 
bolts fitting into the table T-slot. The base is provided 
with two sets of holes to allow for moving the vise, when 
set in a vertical plane, in order to clear the milling ma- 
chine spindle. 

Universal Index Centers. The centers of the universal 
index shown in Fig. 331 wing 12 and one-half inches in 
diameter. 

The head can be set at any angle from 10 degrees h,e- 
low the horizontal to 10 degrees beyond the perpendicular. 

The spindle is provided with a face plate and adjustable 
dog carrier. The front end has a No. 12 taper hole. The 



MACHINE TOOLS 



423 




424 



MACHINE SHOP PRACTICE 



straight hole at the end of the taper is one and one-half 
inches in diameter. 

The Worm Wheel is 6 inches in diameter, and one rev- 
olution is made by 60 revolutions of index crank. 




Fig. 332. 



The Foot-stock Center can be raised vertically and set at 
an angle in a vertical plane. 

Index Sector. The index crank is adjustable, and the 
sector arms graduated. 

The Index Plates divide all numbers to 100, all even 



MACHINE TOOLS 



425 



numbers to 134. The index table furnished gives all the 
divisions obtainable to 372. 

The Table is provided with flanges, and is 32 inches 
long, 8 inches wide, and has 3 T-slots three-quarters of an 
inch wide. 

The Center Rest will take work to 3 and one-eighth 
inches in diameter. 




Fig. 333. 

Vertical Spindle Milling Attachments. The attachment 
shown in Figs. 332 and 333 are used for a large range of 
light milling, as key-seating, die-sinking, T-slot cutting, 
spiral milling, sawing stock, and work of a similar charac- 
ter. 

In die-sinking, as well as all kinds of surface milling, 
the advantage of having the work operated upon in plain 
sight of the operator is readily appreciated by tool-makers 



426 



MACHINE SHOP PRACTICE 



and machinists. For metal patterns and similar work the 
attachments are especially valuable, as a line or template 
can be followed very closely, thus reducing the hand fin- 




ishing to a minimum. The attachments are also of great 
advantage for spiral milling on universal milling machines. 



MACHINE TOOLS 427 

In milling spirals in the usual way, many times the work 
is a considerable distance from the end of the spindle, as in 
cutting spiral gears, thus necessitating the use of long ar- 
bors which are liable to spring. By the use of the attach- 
ment, however, the machine is geared for the required lead 
and the attachment set to the angle of the spiral. The table 
thus remains set at zero, a short arbor is used, and the 
cutting may be done on the side or top of the piece in 
hand. 

Differential Dividing Head. The body of the head shown 
in Fig. 334 consists of a base with annular and parallel 
housings, a center block carrying the spindle, a worm 
gear and pinion, and the trunnion supporting plates for tk« 
center block. Spur and spiral gears may be cut on this at- 
tachment and bevel gears on the head alone. 

Speed for Milling Cutters. The milling cutters shown at 
A in Fig. 335 are of a form in general use. They have straight 
teeth arranged at equal distances on their face parallel 
to the axis, and radial teeth on one side, as shown. When 
two of these mills are arranged in pairs, or when a single 
mill has teeth on its face and on two sides, it is called 
a straddle mill. 

Should a mill have a wide face, the teeth are cut spiral- 
ly, as shown at B. Wide, straight teeth would not main- 
tain a uniform cut on entering or leaving the work. With 
spiral teeth the cut begins at one end of the tooth, the cut 
being started, the cutting is uniform, producing smooth 
work, and avoiding any sudden shock when entering or 
leaving the cut. 

The milling cutters are provided with a center hole, which 
fits on an arbor shown at C, and are also provided with 
a keyway, shown in the illustration, the end of the arbor 
fitting into a conical seat, is securely held in the machine 
spindle, permitting the arbor to revolve in either direc- 
tion without becoming released. The milling cutters can 
be reversed on the arbor, and the feed of the work can be 



428 



MACHINE SHOP PRACTICE 



H 








Mm 

1 il D 1 : 


1 I II 

1 i 1 

■ 1 H HP 




Fig. 335, 



MACHINE TOOLS 429 

changed, it is plain, could not be done if the mill was on 
\n arbor that screwed upon the driving spindle of the 
machine. 

As the proper speed of the cutters is essential to the 
economical production of work done by milling machines, 
the following Table No. 20 will be found of great use. 

A narrow face cutter commonly known as a slitting saw 
is shown at E and a set of end milling cutters at D. An 
adjustable chuck or collet H for holding the end milling 
cutters shown at D, and the spanner wrench for tightening 
and loosening it at G. 



430 



MACHINE SHOP PRACTICE 



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MACHINE TOOLS 



431 



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432 



MACHINE SHOP PRACTICE 



As the speed of the cutter varies considerably with the 
kind of material to be operated on, and as it is generally 
the case that the machinist will be called upon to use his 
own judgment. Table No. 21 may be safely taken as a 
guide. 



Table No. 21 — Speeds for Milling Cutters. 




Brass 


Cast Iron 


Machine 
Steel 


Tool Steel 
Annealed 


Feet per minute 


80 to 120 


40 to 60 


35 to 45 


25 to 35 


Feed per minute 
in inches. 


lXto2 


XtoiX 


Z A to 2 


MtoX 



Example: What should be revolutions per minute for a 
6 inch cutter to operate at cutting speed of 50 feet per 
minute. 

Answer: From Table No. 21, with 50 feet per minute 
cutting speed and a diameter of 6 inches, the revolutions 
per minute will be found to be 31.$ 





Fig. 336. 

In general practice it is found to be more satisfactory to 
run the milling cutters up to the maximum speed, with a 



MACHINE TOOLS 



433 



comparatively light feed, than to reduce the speed of cut- 
ters and overfeed the work. 

Milling Cutters. A variety of milling cutters are illus- 
trated herewith. 

Fig. 336 shows two forms of face milling cutters. 

Fig. 337 is a sprocket milling cutter to cut the teeth of 
sprocket wheels which is a block chain. 




Fig. 337. 




Fig. 338. 



Fig. 338 in a cutter which is used to cut the teeth of in- 
volute gears. 

Fig. 339 in a cutter for gears having the epicyloidal form 
of teeth. 

Fig. 340 is what is known as a stocking cutter, and is 
used to cut out the stock in a gear blank before finishing 
with the proper cut. 

The use to which the milling cutters shown in Figs. 341 
and 342 are put in fully explained in the illustrations 

Milling Operations. Twelve different milling machinf 



434 



MACHINE SHOP PRACTICE 







Fig. 339. 

operations are illustrated in Fig. 343, which show almost 
every possible conditions of work. They may be of great 




Fig. 340. 

value to a machinst when debating in his mind as how 
best to perform just such an operation. 



MACHINE TOOLS 



435 






I 





436 



MACHINE SHOP PRACTICE 




W 



1 






.: 



v" ; ' 



436 






wmm 








MACHINE TOOLS 437 



PLANERS. 



Planing Operations. The operation of planing consti- 
tutes cutting in a straight line by means of a steel cutting 
tool. In the planer, the piece to be planed is moved in 
a straight-line under a stationary tool. The planer is a 
very important tool to the printing press builder, as well 
as in the production of lathe beds, slides and parallel. 

The work to be planed is securely fastened to the table 
of the planer, and is moved backwards and forwards by 
means of suitable gearing the cutting tool being held in the 
tool post, mounted upon the cross-slide. 

The mechanism feeding the cutting tool, and regulating 
the travel of the table in planers are of different forms. 
The general practice is: The employment of two belts, one 
for the forward and the other for the backward travel of 
the table. The feeds are operated by independent devices, 
the attachments on the planerbed being used only to shift 
the belt. 

The track and pinion movement is usually employed on 
nearly all planers to give the longitudinal travel to the 
table. 

43x43-inch Planer. This machine planes 43 inches wide. 
43 inches high and can be built to plane any desired 
length. 

The bed is of ample length and well braced with cross 
girths of box form, and automatic lubricators are provided 
for oiling the table V. 

The table is driven by cut gearing and rack and its mo- 
tion can be controlled from either side of machine. 

The driving works can be arranged for the machine to 
stand parallel with or at right angles to the line shaft. 

The feeds are positive, operating the tools at any angle. 
The cross-rail is of box girder form Avith deep arched 
back, is of sufficient length, when using two saddles, to 



438 MACHINE SHOP PRACTICE 

permit of one head planing the entire width between the 
uprights. 

The uprights are of the double plate construction, in- 
suring rigidity for side cutting. 

Fig. 344 shows the machine with four heads, but any of 
them may be left off if so desired. 

32-inch Planer. Planer, which planes 32 1 /2x32 1 / £ inches 
high and Fig. 345 shows a 32-inch plane any length from 
8 to 16 feet, as desired. 

The bed is of extra depth, and of unusual length, in pro- 
portion to that of the table, so that the table projects but 
little when planing at full length. The distance between 
the Vs is sufficient to prevent any tipping of the table 
when taking a heavy cut at the extreme sides. 

The table is deep and very rigid. T slots are planed its 
entire length, the holes are drilled and reamed from the 
solid. Holes are also bored at the end of the table out- 
side the pockets, thus enabling work or extra length to be 
planed. The Vs have broad bearing surfaces, they are 
constantly supplied with oil by perfect lubricating devices. 

The housing are of box form, and have wide bearings 
directly on the bed, insuring the greatest stiffness. 

The cross rail is strengthened by an arch-shaped orace 
on the back, fastened to the uprights by gibs. The elevat- 
ing gears, having a ratio of 2 to 1, enable the cross rail 
to be raised or lowered easily. 

The head is furnished with power feed in all directions, 
operated from either end of the cross rail. 

An important shifting device reverses the table without 
shock or jar, entirely obviating all the disagreeable noise 
of belts in shifting from one pulley to another. The back 
dog can be lifted so the table may be run from under the 
tool to enable the operator to examine his work. The 
points of contract between the shifter and the dog are 
provided with steel rollers, which prevent that' tendency to 



MACHINE TOOLS 



439 




440 



MACHINE SHOP PRACTICE 



excessive wear which usually takes place at these points. 
The table has a returning speed of 3.5 to 1. 

The bull wheel is stationary on its shaft, and the shaft 
revolves in long bearings of large diameter, provided with 
perfect facilities for lubrication. 




Fig. 345. 

All the driving shafts are made of special hammered 
steel of large diameter, they run in well lubricated bear- 
ings. Each shaft, with its appurtenances, may be taken out 
intact when for any reason it is necessary to take the 
planer apart. The loose pulleys are self oiling. 

All gears and racks are accurately cut from solid stock. 
The gears are interchangeable and can be replaced at a 
moment's notice. 



MACHINE TOOLS 



441 



24-inch Planer. The planer shown in Fig. 346 is made 
to handle light and medium work rapidly. 

The bed is of extra length, giving the table almost a full 
bearing when planing at the extreme length. It is sup- 
ported by a center leg, making it very rigid. The Ys are 
wide and provided with oil pockets at short intervals, thus 
insuring perfect lubrication to the table at all times. 




Fig. 346. 

The housings art of the box form, and have an extra 
wide face. The crossrail is well supported on the back, 
and securely bolted to the housings. It may be raised or 
lowered from either side of the machine. 

The table has T-slots planed its entire length. The holes 
in ihe table are drilled and reamed from the solid. 



•442 MACHINE SHOP PRACTICE 

The head has power horizontal, vertical and angular 
feeds, operated from either end of the crossrail. 

An improved shifting device makes it possible to return 
the table without shock or jar. This is accomplished in 
such a manner as to entirely obviate any disagreeable noise 
of the belts, owing to a high belt velocity. The arrange- 
ment removes one belt from the tight pulley before the 
other engages it. The back dog can be lifted so the table 
may be run from under the tool to enable the operator 
to examine his work. 

All the driving shafts are made of special hammered 
steel, and run in well lubricated bearings. Each shaft, 
with all its parts, may be taken out intact, when for any 
reason it is necessary to take the planer apart. The loose 
pulleys are self oiling, a feature of great importance. 

All the gears and racks are accurately cut from the 
solid and all parts are interchangeable, and can be re- 
placed at a moment's notice. 

All the working parts are accurately scraped and fitted 
and each machine undergoes a thorough test and inspection 
before leaving the shop. 

An improved adjustable countershaft is furnished with 
each planer, having tight and loose pulleys, 8 inches in 
diameter for a 3y 2 inch belt, and should run 42*0 revolutions 
per minute. 

Cutting Speed and Feed of Planer Tools. The term 
cutting speed, as applied to machine tools, means the num- 
ber of feet of cutting performed by the tool, in a given 
time, or what is ths same thing, the number of feet the 
shaving, cut by the tool in a given time, would measure 
if extended in a straight line. The term feed, as applied 
to a machine tool, means the thickness of the cut or shav- 
ing taken by the tool. 

As planing machines are usually constructed so that their 
carriage or table runs at a fiseal and unchangeable speed, 
the cutting speed is fixed, and the operator has therefore, 



MACHINE TOOLS 



443 



to consider the amount of feed to be given to the tool at 
a single cut, which may be placed at a maximum by keep- 
ing the tool as strong as possible in proportion to its work 
and making it as hard as its strength will allow, and at- 
taching it so that its cutting edge will be as close to the 
tool-post as is possible. Cast-iron may always be cut in a 
planer with a coarser feed than is possible with wrought- 
iron or steel. 



A 







CI 



t4^ , 




Fig. 347. 



Fig. 348. 



Planer Tools. Two forms of planer tools are shown in 
Figs. 347 and 348 respectfully. A denotes the point from 
which the tools will spring, in consequence of any in- 
crease in the depth of the cut or from any seams or hard 
places in the metal. As a result of this spring, it will be 
obvious that the tool shown in Fig. 347 will dig deeper 
in the cut, when the pressure due to the cut is increased 
in the direction indicated by the arrow. It may be read- 
ily seen by reference to the drawings that the radius from 
the point of support at A to the point T of the tool is 



444 



MACHINE SHOP PRACTICE 



greater in Fig. 347 and in Fig. 348, although both tools 
are at a like height from the face of the work. While 
these two tools are the extremes of the forms shown, a 
compromise between the two may be had by making the 




1 






5 

7 





Fig. 349. 

point or cutting edge of the tool in line with the center 
of the tool. Thus making the tool easier to forge and also 
keep the cutting edge is plainer view when at work. 

A set of planer tools are illustrated in Fig. 349 and a 
description of them in use is given herewith: 



MACHINE TOOLS 



445 



No. 1 is a left-hand side-tool. No. 2 a right-hand side- 
tool. No. 3 is a left hand diamond-point tool and No. 4 a 
right-hand diamond-point tool. No. 5 is a broad-nose or 
stocking-tool for taking heavy cuts with and No. 6 a scaling 
tool from removing the outer surface from a rough cast- 
ing. No. 7 and 8 are right and left-hand siding tools while 
No. 9 is a finishing-tool for getting into sharp corners. 
No. 10 is eutting-off tool, while Nos. 11 and 12 are right 
and left bevel tools. 

Planer Jacks. These jacks shown in Fig. 350 are design- 
ed for tool-room use, for leveling up work on a planer- 
bed or under an upright drill and for setting up machin- 
ery. All the parts are case-hardened. 




Fig. 350. 



The Jack A has a range from 2V 2 to 3% inches. It will 
raise 1,000 pounds or more. The two extension bases E 
and C are made to fit the base of the main part A and are 
1 and 2 inches high respectively. "With these two exten- 
sions used singly or together a reach of from 2% to 6^ 
inches may be obtained. 

An auxiliary pointed screw D is supplied to be used in 
place of the screw shown at A and in certain places where 



446 MACHINE SHOP PRACTICE 

it mav be preferable. The base E is also provided, for 
use in cases where such a shape may be desirable. 

Planer Vise. A swivel vise for use on the bed or car- 
riage of a planer is shown in Fig. 351. It is bolted upon the 
bed and travels with it, the work being held in the jaws, the 
same as in a vise or a lathe chuck. It may be swung around 
in any direction and is graduated around the base. 




Fig. 351. 

The planer chuck has a round swivel base, and can be 
set at any desired angle. The round pin, as shown in posi- 
tion on side of upper piece, is tapered, and fitting into a 
tapered hole holds the chuck parallel with the base. By 
withdrawing the pin and turning the chuck one-quarter, 
the pin again drops into position, and the chuck is at right 
angles with its former position. One entirely new feature 
is the movable cross piece, with two setting-up screws and 
the two pins shown in position, to prevent same from slip- 
ping. It requires no blocking to follow up the work. Will 
hold irregular work nicely, and is very easily adjusted. 



MACHINE TOOLS 447 

SHAPERS. 

The sbaper is a straight-line cutter of the planer type. 
They perform a large variety of operations formerly exe- 
cuted by hand work. 

In this machine the work is held stationary and the tool 
given a reciprocating cutting motion. 

The feed-motion of shapers may be given either to the 
cutting-tool or to the work. When the feed is given to 
the cutting-tool the machine is described as a travel-head 
shaper. 

In small shapers the feed is communicated to the work- 
table, the head having no side travel, the feed motion be- 
ing given to the table carrying the work. 

The shaper is a very useful tool, and is made in a var- 
iety of forms for special purposes, the work ranging from 
key seats in shafting to planing valves and stearn ports of 
engine cylinders. 

Crank Shaper. The shaper shown in Fig. 352 is strong 
and capable of taking a heavy cut. 

The column is of unusual depth and width, and is also 
strongly ribbed and braced internally, and the ram slides 
project both in front and back. 

The ram is of form designed to resist working strain, 
and is ribbed and braced internally. 

The rail is heavy, ribbed horizontally and strongly gibbed 
to the column, and the cross traverse screw is provided 
with a graduated collar reading to thousandths of an inch. 
There are felt wipers between the rail and the column. 

The head swivels to any angle and is graduated. The 
locking device is simple and efficient, and the down feed 
screw is provided with a graduated collar reading to thous- 
andths of an inch. 

The vise is of an improved double screw form, and has a 
graduated swiveling base, which permits straight or taper- 
ing pieces to be securely clamped with equal facility and 



448 



MACHINE SHOP PRACTICE 



with rapidity. The jaw plates are of annealed tool steel. 
Ball bearings are provided under the elevating screw 
for raising- the rail. 




Fig. 352. 

The key-seating- of shafting and similar work, up to a 
diameter of 2y 2 inches, is provided for by an opening 
through the «olumn under the ram. 

High Duty Crank Shaper. The shaper illustrated in Fig. 
353 is of new design and meets in every respect the re- 
q' irements of modern machine-shop practice. It has the 



MACHINE TOOLS 



449 



power in it and is built to withstand the extra stress inci- 
dent to the use of high duty cutting steel. The motion 
gives the forward stroke an even cutting speed the entire 
length of the cut, together with a quick return that is 
twice that of any other crank shaper made. 
The column is of the latest box pattern. 




Fig. 353. 

The base is extended well out in front for the table support. 

The ram is of the box pattern. It is well ribbed and 
strong in design. 

The head has its swivel accurately graduated and can be 
set to any angle and is held in position by two bolts. 

The slide has a travel of 9 inches. The screw is pro- 



450 MACHINE SHOP PRACTICE 

vided with a graduated collar which reads to one-thous- 
andths of an inch. The collar is so arranged that it can 
be set to read from zero at all times without regard to the 
position of the screw. 

The table is of the box form with working surface on top 
14x20 inches. Both sides have three T slots for clamping 
work. The table is raised sufficiently above the saddle 
to allow for T bolts to be placed from either end of table. 
The table hooking over the saddle gives extra rigidity. 
The table can be readily removed from the saddle, which 
also has three T slots for clamping work to it. All T slots 
are cut from the solid metal. 

The table support furnished is very strong and rigid and 
supports the table its entire width when in any position on 
the bar. The sliding parts are all hand scraped and well 
gibbed. 

The stroke is very powerful and in uniform the entire 
length of the cut with a quick return. An index and 
pointer in plain view shows the length of stroke. 

The back gears are thrown out or in by means of a lever 
within easy reach. 

The cross feed is 26 inches in length and is automatic 
in either direction. The feed is operated through a rod 
which adjusts itself to any position of the bar, and it in 
turn is operated by means of a new feed, so made that 
adjustment may he had when the machine is in motion. 
The screw is fitted with a graduated collar reading to one- 
thousandths of an inch the same as on the down feed. 

The vertical movement of the table is by means of bevel 
gears and a telescopic screw having ball thrust bearing. 

The rocker arm is made so that a 4 inch shaft can be 
passed through under the arm for keyseating. 

The vise is of the swivel base pattern and is clamped 
in position by two bolts, and is without spring under the 
heaviest cuts. It is not made too heavy and clumsy for 
Aofivenient handling. 



MACHINE TOOLS 



451 



The driving-cone has four steps for ihree-inch belt, the 
largest step being fourteen inch diameter. It is supported 
between two bearings, one on the column and an outboard 
bearing, which makes it very rigid. 

The countershaft is provided with self-oiling boxes, and 
has tight and loose pulleys fourteen inches in diameter for 
four inch belt. 




Fig. 354. 

^ Motor Driven Shaper. In the shaper shown in Fig. 354 
it will be noticed that the idler is connected with the driv- 



452 MACHINE SHOP PRACTICE 

ing pulley through gears. The advantage in this is very 
obvious. Were it possible for the belt on the motor pulley 
to slip, the idler, through the gears, would then become 
the driver. Also the large amount of belt contact which 
can be had makes this about as positive a drive as a chain. 

The motor has a 300 per cent variation through the field 
control, giving in all, with the back gears, 52 changes in 
ram speed. The ram can be stopped or started in any posi- 
tion without stopping the motor. 

Pull-Cut Traverse Head Shaper. The machine illustrated 
in Fig. 355 has a bed very wide and deep, and strongly 
braced and ribbed, which is very rigid, and, as it rests 
upon broad and substantial bases, the vibration in the ma- 
chine is reduced to a minimum. 

The saddles, which carry the rams, have long and wide 
bearings, provision for taking up wear, and are arranged 
for quick return by hand. They are operated by full length 
and separate screws consequently the rams may be operated 
independently, and the saddles close together even at either 
extreme end of the bed. 

The rams are made of extra width and of a form which 
gives great stiffness and ample wearing surfaces, and being 
operated by the Whitworth motion, have a quick return mo- 
tion. They are provided with a rack and removable pinion 
wrench for positioning, both for length of stroke and for 
position over the work. This is said to be the most effi- 
cient and positive arrangement for accomplishing this re- 
sult yet devised. 

The feeds are located on the saddle, are automatic, and 
allow the amount and direction to be quickly and easily 
changed while the machine is in motion. The range of finer 
feeds is obtained through the feed screw and finishing feeds 
or rapid traverse of saddles by means of the rack. 

Micrometer collars, reading to thousandths of an inch, 
are on the down feed screws in the heads, and also on the 
traverse screws, operating the saddle. 



MACHINE TOOLS 



453 




454 



MACHINE SHOP PRACTICE 



The head is strong and substantial in construction, and 
is provided with a simple and reliable variable automatic 
down feed, and also with a worm for doing circular work. 

The aprons have three bearings on the bed, which, as 
stated, is unusually deep, and are movable along it by 
means of a rack and pinion and removable pinion wrench. 

The two tables, movable vertically on the aprons and hor- 
izontally with them along the bed, are provided. 

The elevating screws for the tables are hung on ball bear- 
ings. 




Fig. 356. 

The vise is of an improved double screw form with 
graduated swivelling base and swivelling jaw, permitting 
straight or tapering pieces to be clamped with equal facil- 
ity and with rapidity. 



MACHINE TOOLS 455 

The gearing is of wide face and large diameter, giving 
ample strength and large wearing surfaces. 

The index centers which are furnished with the machine, 
swing 8 inches and take 17 inches between centers. 

A two speed countershaft, giving eight cutting speeds to 
the ram, is furnished with the single geared machine, while 
the back gearing in the back geared machine gives eight 
cutting speeds. 

Fig. 356 is an illustration of one of the heads of the 
Traverse Head Shaper shown in Fig. 355. 

Rack Shaper. The machine illustrated in Fig. 357 has 
ample metal throughout to make it a powerful and ac- 
curate tool and give it great rigidity under working strain. 

This machine being built on the four shaft planer prin- 
ciple, is triple geared, that is, has three increases of power 
between the driving pulley and the ram. Thus affording 
a cutting power proportionate to the strong construction of 
the machine. 

The column is of unusual depth and width, and is also 
strongly ribbed and braced internally, and the ram slides 
project both in front and back. 

The ram is provided with a double rack, thus avoiding 
side thrust, and is ribbed and braced internally. 

The rail is heavy, vertical!}' ribbed and is strongly gib- 
bed to the column, and the cross traverse screw is provided 
with a graduated collar reading to thousandths of an inch. 

The head swivels to any angle and is graduated. The 
locking device is simple and efficient, and the down feed 
screw is provided with a graduated collar also reading to 
thousandths of an inch. 

The vise is of an improved double screw form, and has a 
graduated swiveling base which permits straight or taper- 
ing pieces to be securely clamped with equal facility and 
with rapidity. Its jaw plates are of annealed tool steel. 

This shaper is supplied with an outer, or table support, 
as shown. 



456 MACHINE SHOP PRACTICE 

Ball bearings are provided under the elevating screw 
for raising the rail. 

The key-seating of shafting and similar work is provided 
for by an opening of large capacity through the column un- 
der the ram. 




Fig. 357. 

All gears and T slots are cut from the solid metal, and 
all the bearings are amply large, and all shafts are ac- 
curately ground in the shop, and the shaft bearings are 
long and well braced in the column casting. Convenient 
means are provided for lubrication. The length of the 
stroke can be changed instantly while the machine is in mo- 
tion. The screws for adjusting gibs in the down slide of 



MACHINE TOOLS 



457 



head, and also the ram slide, are held in position by lock 
nuts, counter-sunk flush with casting. 

Speed Change Gear Box. The Gear Box drive shown in 
Fig. 358 provides all the changes of speed obtainable 




Fig. 358. 

through the usual cone pulleys and also has the further 
advantage of affording a large and constant area of belt 
contact at all speeds, without shifting the belt. 



458 



MACHINE SHOP PRACTICE 



In designing this gear box, it has been the aim t® make 
it as simple and strong as possible. In the gear box there 
are three shafts, two of which carry sliding gears. Hand 
nuts readily move and lock these gears. This gear box if 
desired may be attached at any time, though it is more 
readily done while the shapers are in process of construc- 
tion. 




Fig. 359. 

16-Inch Back-Geared Crank Shaper. The tool shown in 
Fig. 359 is of entirely new design, and has a number of 
valuable features, viz: 

The column is of unusual depth and width, and is strong- 
ly braced internally. The bearings for the ram project both 
front and back. 

The ram is unusually long and wide, it is scraped to a 
perfect bearing in the column, its position of travel can 



MACHINE TOOLS 459 

be changed while the machine is in motion, through the 
hand wheel shown near the head of the ram, which operates 
a screw through the spiral gearing. 

The length of stroke of the ram can be changed while 
the machine is running, by means of a hand wheel on the 
right-hand side. Various lengths of stroke are indicated 
by a pointer on the side of the ram, which travels along 
an index plate. 

The tool head is graduated into degrees. The down- 
feed screw is provided with a collar at the top, graduated 
to thousandths of an inch. 

The crank is single geared at a ratio of 4.76 to 1. With 
the back gearing it gives a ratio of 10 to 1, making with a 
five-step cone a range of ten speeds, which is especially 
valuable for tool-room use, when it is necessary to change 
quickly from working brass or cast iron, to steel, or vice 
versa. It is changed from single to back geared by means 
of a lever located at the rear of column. 

The table is fitted to the saddle by overhanging on the 
top and locked into the back of the same by a right-angle 
corner. Each bearing of the table is fitted to the saddle 
by scraping, insuring accuracy and great stiffness. This 
style of fastening the table to the saddle is not common 
with shapers, yet it is a feature of great merit. 

The table has three T slots on the top and either side. 
On the right-hand side of the table there is a hole bored 
to receive the stud of the vise, so that the vise may be 
held on the side as well as on the top. There is also a 
vertical V groove planed in the opposite side of the table, 
which is convenient for holding shafts, round bars, etc. 

This tool has a new feature which is entirely original. 
It is the planing of grooves across the top of the table at 
right angles to the traverse of the ram. This will be found 
serviceable in locating a parallel strip so that work can be 
held at right angles when desired without loss of time ia 
squaring the same. 



460 MACHINE SHOP PRACTICE 

Tli 3 elevating screw is of large diameter, and is provided 
with ball bearings, which will be found most effective in 
action when raising or lowering the cross rail. The elevat- 
ing gears are made of steel and are cut from the solid. 

Another entirely new feature, original with this machine, 
is the quick return of the saddle of 2 to 1. This will be 
found of great value. 

A tool shelf is placed on the right-hand side of the ma 
chine for holding oil can, wrenches, etc. 

The vise furnished with this machine has tool steel-faced 
jaws and tool steel center points, securely held into the 
top of either jaw. With the vise is furnished an extra pair 
of angular jaws for holding irregular shaped pieces, that 
will be found serviceable for many classes of work. 

The base of the vise is graduated into degrees. 



Fig. 360. 

The movable jaw can be securely clamped by two bolts 
on either side of the same. The screw which operates this 
jaw is protected at all times from dirt and chips. 

The keyseating of shafts and similar work up to a dia- 
meter of 2 1 / 4: inches is provided for by an opening through 
the column under the ram. 

The connection or the rocker arm with ram is accomplish- 
ed bv an improved method. 

Shaper Centers. The drawing shown in Fig. 360 repre- 
sents a pair of shaper centers, but they can be used on 



MACHINE TOOLS 461 

planers and milling machines as well. They swing 7 inches 
in diameter and take between centers 13y 2 inches. 

The stationary center has y 2 inch vertical adjustment 
above or below the centers, and is securely held in a head 
that is cast with the body. 

The index head slides on a dovetail planed on the top of 
the body, and with one bolt can be securely clamped at 
any place according to the work. 

The index is formed by having six circles of holes drilled 
in the back of the face plate, giving the following divi- 
sions: 48, 52, 54, 56 and 60. The spindle is fixed at any 
place by means of an index pin, that can be solidly fastened 
so as to coincide with any of the holes. 

The spindle is bored to a No. 3 Taper and can be securely 
clamped when set, taking all strain off the index pin. 



462 



MACHINE SHOP PRACTICE 



SLOTTING MACHINES. 

The slotting- machine may be classed as a vertical shaper, 
it performs straight line cutting. The tool, as in the 
shaper, has a longitudinal movement, the bed or table being 
stationary, except for the transverse feed movement. 

There are many varieties of slotters. The small ma- 
chines are usually crank-driven or friction driven. The 
larger ones have 
racks and pin- 
ions driven by 
a train of spur 
gears, with shif- 
ting belts. 

The principal 
features aimed 
at are smooth 
running and 
convenient 
handling of 
the work. 




Fig. 361. 

The advantageous features of the slotter are, that the 
work is always visible, the line to be worked to being on 
top where the tool begins to cut, instead of where it fin- 
ishes the cut as in the case of the shaper. 



MACHINE TOOLS 



463 



For cutting- the keyways in wheels or pulleys of large 
diameter, the slotter has no equal. 

10-inch Slotter. The slotter shown in Fig. 361 is a well 
designed and convenient tool to operate, and as shown is 
very powerfully back geared. 

The bar in easily adjustable by means of a crank in front 
of the bar, is counter-balanced, and has the Whitworth 
quick return motion. The tool block has a relief motion 
for the cutting tool. 

The table has power feeds in all directions— lateral, cross 
and circular. 

18-inch Slotter. 

The machine 
illustrated in Fig. 
362 has a stroke of 
18% inches, with 
an adjustment for 
any position and 
length of move- 
ment. . 

The cutting bar 
has eight speeds, *g 
it is counterbal 



anced 
turns 



and 
with 



re- 
a 




Fig. 362. 

speed of 3 to 1; it is furnished with a vertically adjusted 
guide and relief tool apron. 



A64 



MACHINE SHOP PRACTICE 



The distance from the frame to the front side of the 
jutting bar is 36 inches, making it possible to slot in the 
center of 75 inches. The distance from the table to the 
underside of the frame is 30 inches. 

The feeds are positive and self acting in all directions, 
operating at the upper end of stroke, the arrangement of 
the handles and other feed works is such, that the opera- 
tor can command full use of them from one position, and 
at the same time watch the cutting tool. 

The compound tables have an adjustment of 42 inches 
longitudinally and 36 inches transversely, and support a 
revolving table 42 inches in diameter, secured in any posi- 
tion by corner clamps. This table is graduated and so ar- 
ranged that the worm can be disengaged, for ready adjust- 
ment of work. 




Cutting Keyways in a Slotter. The operation of cutting 
a keyway in a large gear or pulley is plainly illustrated in 
Fig. 363. 



AUXILIARY MACHINE TOOLS 



Arbor Press. An arbor press is used for forcing arbors 
into and out of work. 

It saves time and finished work. It saves springing and 
battering the arbor and work. 

It saves splitting the work and chipping the end of the 
arbor which comes from the usual method of driving the 
arbor b}^ means of a hammer or sledge. 

It saves cleaning out the centers and taking off the lathe 
dog when changing pieces. 

Hundreds of these presses are being uSed for purposes 
other than pressing arbors, such as broaching, punching, 
bending with dies, and many other uses. 

Fig. 364 shows a machine, which is a very useful device, 
being quick in action, and which is always ready for use. 
Operated by a hand lever, a pressure of seven and a-half 
tons can be obtained by an ordinary man by means of the 
gear-wheels shown to the right in the drawing. It is ex- 
ceedingly simple in action, and consists of a massive stand- 
ard, which carries a sliding or adjustable knee which can 
be regulated to the height of the work by a square-thread 
screw, which acts in a nut in the top of the standard. 
The handle wheel operates the screw while the plate is 
free to revolve on the knee, and is provided with lateral 
openings of graduated sizes for various dimensioned man- 
drels. When released from the work, the arbor or mandrel 
drops on a soft babbitted cushion and is caught or retained 
in the large steel ring shown below. The plunger or ram 
has a rack cut on one side. This rack is engaged with 
two pinions, one on a seperate spindle and one on the lever 
spindle, they are geared together by the spur wheel shown.. 
The leverage is obtained by means of a wheel and pinion 

467 



468 MACHINE SHOP PRACTICE 

covered in the drawing by the ratchet. A pawl fits into 
the casting, into which a lever is fixed. A leverage of 135 
to 1 is thus obtained. The counterweight balances the 



Fig. 364. 



iever and keeps it in an upright position when not in use. 
A pin projects from one side of the pawl, so that when 
the lever casting is upright, the pawl rides the shedder, 
thus disengaging the pawl from the ratchet, and leaving 



AUXILIARY MACHINE TOOLS 



469 



the ram free to be moved up or brouj 
by means of the hand-wheel. 



it down to the work 




Fig. 365. 

Fig. 365 shows a very powerful press, designed for man- 
drels up to 6 inches diameter. The leverage is 250 to 1 
and the press is capable of exerting a pressure of about 
sixteen tons at the end of the screw. 



470 MACHINE SHOP PRACTICE 




Fig. 366. 

A simple form of an Arbor press is shown in Fig. 366. 

Bolt-Cutting and Threading Machines. Bolt-cutters, like 

other machines, require additional tools and devices, ac- 



AUXILIARY MACHINE TOOLS 471 

JL 




cording to their general construction. An example of this 
Is the special cutting-off tool designed to reduce round 
wrought iron to the length necessary for heading in a bolt- 



472 



MACHINE SHOP PRACTICE 



heading machine. Another example is the power feed-at- 
tachment, which is applied to the machine, to produce 
coarse threads true to pitch. 




Fig. 369. 

Fig. 367 shows a view of a 1%-inch belt-driven bolt-cut- 
ter, and Fig. 368 a lV 2 -inch Motor-driven triple bolt cut- 




Fig. 370. 

ter. Fig. 369 is a 3-inch bolt-cutter with a quick-change 
gear attachment. 



AUXILIARY MACHINE TOOLS 



473 



Table N 


o. 22 — Speed 


op Bolt-Cutter Dies. 


Diameter of Bolt. 


Revolution of 
Dies. 


Diameter of Bolt. 


Revolution of 
Dies. 


X 


460 


IX 


50 


X 


230 


IX 


45 


5 
TIT 


188 


1% 


40 


% 


153 


IX 


38 


7 
T"6" 


131 


1% 


35 


X 


115 


1% 


32 


9 


102 


1% 


30 


% 


93 


2 


28 


% 


75 


2X 


25 


% 


65 


2X 


22 


1 


55 


2% 


20 






3 


18 



Table No. 22 gives the cutting speed for bolt cutter dies 
iix revolutions per minute for the die holder or head. 

The screw-cutting die head shown in Fig. 370 is simple 
in construction and yet admits of the finest adjustments, 
being graduated upon one side of the shell and provided 
with an index by which quick and accurate variations in 
the diameter of the threads may be made. As the index 
is controlled by one screw all the dies are adjusted simul- 
taneously. 

The construction of the dies and the method of holding 
them is such as to allow a thread to be cut flush up to a 
shoulder if desired, and by means of an internal adjustable 
gauge either long or short threads may be cut. 

In operating the dies the gauge is set for the length of 
thread required, and as the stock passes through the dies 
and comes in contact with the end of the gauge, the 
mechanism of the die head is instantly unlocked and the 
dies open automatically, thus releasing the work. The 
dies are closed again by means of a small handle provided 
for the purpose at one side of the head, or they may be 
closed automatically, if desired, by screwing a pin into the 



474 



MACHINE SHOP PRACTICE 



threaded hole opposite the handle and attaching a small 
piece of flat steel to the back edge of the turret slide, 
which will engage the pin as the turret revolves, thus 
bringing the die head around into position with the dies 
closed for the next operation. 

The advantages of this method of thread cutting, when 
compared with the old way of running the work into a 
solid die and then being obliged to reverse the motion of 




Fig. 371. 
the machine in order to allow the die to run back, can be 
readily appreciated. Not only is there a great saving in 
time, but other well known objections to the solid die, such 
as stripping of the thread, or otherwise injuring either 
thread or die when reversing the motion of the machine, 
are wholly obviated. 
Brass Finishers' Lathe. Fig. 371 represents a brass fin- 



AUXILIARY MACHINE TOOLS 



475 



isher's lathe, which is used extensively in the manufacture 
of brass goods requiring several operations. 

The headstock is provided with an adjustment to main- 
tain a perfect alignment of the spindle. 

The spindle is made of special hammered steel, accu- 
rately ground, and runs in phosphor-bronze bearings, with 
provisions for taking up the wear. 




Fig. 372. 

The bed is of box form, and dovetailed on the top, mak- 
ing the best construction for a lathe of this kind. 

The turret revolves automatically. The indexing mech- 
anism is made of hardened steel, the locking pin is forced 
into the various divisions by a spiral spring, the tension 
of which can be regulated to suit requirements. 



476 MACHINE SHOP PRACTICE 

The cut-off rest is operated by rack and pinion. It has 
two tool posts, fitted with adjustable taper wedges for reg- 
ulating the 'height of the tools. 

The countershaft has double friction pulleys, ten inches 
in diameter for a three and one-half inch belt, and runs 
360 revolutions per minute. 

Fig. 372 shows the details of the turret of the lathe de- 
scribed herewith. 

1. Turret slide and binder. 

2. Turret showing hardened steel ring and ratchet. 

3. Lock bolt cover. 

4. Turret slide rack, cut from steel. 

5. Hook bolt. 

6. Lock bolt, hardened and ground. 

7. Lock-bolt lever, hardened and ground. 

8. Lock-bolt gib. 

9. Pilot wheel, showing rack pinion sleeve and shaft. 
10. Base of turret, showing turret slide gib and binder. 




Fig. 373. 

Centering Machine. A centering machine for drilling 
and countersinking the ends of round stock or shafting is 
shown in Fig. 373. It consists of a live spindle with two 



AUXILIARY MACHINE TOOLS 



477 




478 



MACHINE SHOP PRACTICE 



pulleys to drive the drill and a universal chuck to hold the 
work during the drilling and countersinking operations. 

Cold Saw Cutting-Off Machine. A cutting-off saw is a 
machine designed for cutting off the ends of work and 
also for cutting it to any desired length, in the ordinary 
machine shop practice, a power-driven hack-saw is used, 
but when cutting large work, a circular, revolving saw is 
used to cut the work cold. This is usually known as a 
cold saw cutting-off machine, and is illustrated in Fig. 374. 

This machine shown can be used for round or square 
stock, and can be arranged for motor drive. 



t ..;|Pflilfc 




Fig. 375. 



A motor-driven cold saw cutting-off machine is shown 
in Fig. 375, which has a friction drive to vary the feed 
of the saw. 

Cutting-off Machine. The cutting-off machine is used to 
cut rods or bars into exact lengths, which saves a great 
deal of time over the old method of cutting them. As the 
bar can be cut in less time, and the cutting-off machine 



AUXILIARY MACHINE TOOLS 



479 



leaves the end of the work square and true and of the 
required length. 




. The spindle of a eutting-off machine is hollow and the 
bar passes through it until it comes up to a stop or gauge 
which determines the distance the bar shall project beyond 



480 



MACHINE SHOP PRACTICE 



the cutting tool, this distance being the length of th« 
piece cut off. Chucks at each end of the live spindle are 
provided to hold and to guide the work. 




Pig. 377. 

The illustration shown in Fig. 376 represents a cutting- 
off machine. This machine will cut off and center the 
stock at one end at the same operation. 



AUXILIARY MACHINE TOOLS 481 

Grinder Attachment. It is often necessary to grind a 
flat surface, and with the ordinary grinder this is impossi- 
ble as there is nothing to regulate the amount to be ground 
off. The attachment shown in Fig. 377 is clamped firmly 
to the frame of the grinder head, and may be turned back 
so as not to interfere with the use of the machine as an 
ordinary grinder, or easily removed. An attachment of 
this kind will be found of great advantage in foundries 
and machine shops where rough fittings is required, and 
for finishing iron patterns. 

Hub-Forming Machine. An automobile hub-forming ma- 
chine is shown in Fig. 378. The hub rest has long bearings 
on the bed, the tools are held in dovetailed grooves in the 
uprights. The rear tool takes the roughing cut and can 
be adjusted independently of the front tools. It is serrated 
to break the chips. The turret is of a combination type, 
having a flange cast around the lower part. The bottom 
of this turret has an annular T-slot, in which a number of 
tool posts can be securely clamped. The turret has the 
usual number of holes in the head, each hole has an indi- 
vidual automatic stop, shown at the end of the turret slide, 
wWn comes into play when the turret is revolved either 
to the right or to the left. These stops can be adjusted 
to suit the work, which is far superior to the old method 
of making each tool of the exact length to suit the work. 
The forming tools are so made that they can be sharp- 
ened without changing their form. The cross feed screw 
has a graduated collar, which is invaluable in producing 
exact diameters. 

A steady rest for supporting the stock is mounted on 
the same base as the hub rest. It is fitted with a pair of 
hardened steel jaws to avoid marring the finished surface 
of the hub. These jaws %re operated by a right and left 
hand screw and will grip stock up to the full capacitj^ of 
the machine. The cut-off tool slide is attached to the side 
of the steady rest and is operated by a lever. The in- 



482 



MACHINE SHOP PRACTICE 




AUXILIARY MACHINE TOOLS 483 

dexing mechanism is made of tool steel hardened and 
ground. The drills used are made hollow, so that oil can 
be forced to the end where the cutting is done. 

The hub is formed and drilled at the same time, the drill 
being driven independently. This is accomplished by a 
telescoped shaft and universal joints, driven direct from 
the countershaft by means of steel bevel gears. The lower 
bracket supporting the bevel gears takes a bearing directly 
on the flange of the turret, thus making a rigid construc- 
tion. Being attached in this manner, the revolving drill 
can be swung around the same as all other tools held in 
the turret. The oil pump constantly furnishes a sufficient 
supply of lubricant to the tools when the head is running 
in either direction. 

All pinions, worms and racks are made of steel. Both 
the worm wheels are bronze. All screws and nuts are case- 
hardened. Each machine is furnished with a set of tools 
for forming the front and rear hubs, one drill, one counter- 
bore, one split collar, and one collet, each for the front 
and rear hubs. 

This machine is said to finish in ten hours twenty pairs 
of hubs from three-inch stock, drilling a one and fifteen- 
sixteenth inch hole three and one-half inches long, reaming, 
counter-boring, forming and cutting off. This with a one- 
half inch depth of flange on the rear hub. The machine has 
a friction geared head with a two-step cone pulley for a 
two and one-half inch belt. The gearing is entirely encased. 
The spindle is made of special hammered steel accurately 
ground. It has a three and one-sixteenth inch hole bored 
through it, so that a bar three inches in diameter can be 
passed through. 

Key-Seating Machine. Fig. 379 shows a machine for 
cutting key seats in pulleys and gears. The work is se- 
curely clamped to the table by means of bolts which en- 
gage in the T-slots shown. The cutter bar is drawn through 



484 



MACHINE SHOP PRACTICE 



the work, the feed being made by the inward movement of 
the table. 

Pipe Threading and Cutting Machine. The threading 
and pipe cutting machine shown in Fig. 380 is said to be 
the most carefully and rigidly built tool on the market. 




Fig. 379. 

The extra long barrel, with a chuck at each end, insures 
the center line of the pipe being symmetrical with that of 
the machine, so that the threads are cut at exact right 
angles to the axis, and several lengths of pipe will be in 
perfect line when joined together. 



AUXILIARY MACHINE TOOLS 



485 



All the machines are equipped with an adjusting mech- 
anism, which requires no tools to operate, and is accurate 
and reliable at all times. By throwing a lever, this mech- 




anism opens the dies to pass clear over the pipe, when the 
attached cutting-off tool can be moved up and brought to 
bear without moving the pipe. 



486 



MACHINE SHOP PRACTICE 




A motor-driven pipe-threading and cutting machine is 
illustrated in Fig. 381. An adjustable six-die die-holder 
for a pipe threading machine is shown in Fig. 382. 



AUXILIARY MACHINE TOOLS 



487 



Power Presses. 

To belt up a power press properly, set it in line with the 
countershaft or main shafting, and fasten it securely to 
the floor, taking care that it is properly leveled, and that 
each leg has an equal bearing on the floor. The better the 
foundation, the better the results that will be obtained. 
Take double the distance from the center of counter or 
main shaft to center of crank shaft on the press, and add 




Fig. 3S2. 

one-half the circumference of both pulley and balance 
wheel, and the result will be the approximate length of 
belt required. If the press is an inclined one, and it is to 
be used in an upright position also, set the press on an 
incline and cut the belt to the proper length; then set it 
upright and set a piece of belt of the proper length to be 
used when the press is in that position. Put on a belt 
the full width of the wheel. Do not put a 2-inch belt on a 
4-inch face balance wheel, and then expect the momentum 
of the wheel to do the rest. Do not set the press directly 



488 



MACHINE SHOP PRACTICE 




Fig. 883. 



under the main or 
countershaft when it 
is possible to avoid 
it. Set it at least 2 
feet away, even if 
floor space has to be 
sacrificed to do so. 
Run the belt with 
the grain side next 
to the pulley. A long 
belt is preferable to 
a short one, as the 
adhesion caused by 
the weight of the belt 
is more desirable 
than that obtar d 
by tight lacin<? >nd 
the belt wil^ wear 
longer aud give bet- 
ter results. 

Drop Press. 

The hammer illus- 
trated in Fig. 383 
strikes a quick, 
sharp blow, at the 
rate of 250 to 500 
blows per minute, 
according to the size 
of the machine, and 
instantly gets away 
from the work, there- 
b y avoiding any 
chilling of the stock. 



AUXILIARY MACHINE TOOLS 489 

Power Press. The crank shaft of the machine shown 
in Fig. 384 is made of a selected double-hammered forging 1 , 
accurately turned, with broad polished bearings of suffi- 



Pig. 384. 

cient diameter and length to give power and efficiency. 

The cam pintle is made of high-grade cast steel, and is 
bushed with brass. 

The main crank shaft bearing has large diameter and 
length, to insure good wear and service, and is bushed with 
brass to make it serviceable and efficient. 



490 



MACHINE SHOP PRACTICE 



The clutch is of the positive- jaw type, with jaws lined 
with hardened tool steel plates, extra thick and carefully 
fitted, and is attached to the shaft by two feathers to in- 
sure strength and avoid binding on the shaft. 




Fig. 385. 



An improved automatic stop is furnished with all ma- 
chines, for stopping the machines at any desired position 
of the stroke. This automatic stop insures positive disen- 
gagement of the clutch by means of an adjustable cast 
steel cam ring on the same, acting against a hardened tool 
steel roller on the top of the stop plunger. 



AUXILIARY MACHINE TOOLS 



491 



The machine is designed with a much higher throat than 
is commonly used, and thus insures a much greater range 
of work, as well as avoiding cramped space for special tools. 

The shaft of the press, illustrated in Fig. 385, is of 
forged steel, journaled in adjustable liners, provided at the 
under side with an adjustable shoe. This feature supplies 
means for taking up wear and for truing the shaft by 
turning it down in case of excessive wear. 




Fig. 386. 

The connection is graduated one thousandth part of an 
inch, the connection screw is made of tool steel, oil hard- 
ened. The recess for the punch is made square. 

Inclining of the press is made convenient, as after loos- 



492 



MACHINE SHOP PRACTICE 



ening the clamping bolts, it can be done with. a few turn* 
of the crank furnished. 

The clutch is cased on the principle of the sliding bolt 
and has two clutching points. A safety device absolutely 
prevents any starting or repeating of the press. 

Automatic knockouts provide means for discharging work 
positively from the punch. 




Fig. 387. 

Pulley Turning Lathe. A pulley turning lathe is illus- 
trated in Fig. 386. This will turn the face and finish the 
edges of the rim of the pulley at one operation. 

A set of tools for use with this machine are shown in 
Fig. 387. 



AUXILIARY MACHINE TOOLS 



493 



Punch and Shear. Fig. 388 shows a double-ended punch- 
ing and shearing machine. 

This machine is double-geared, and the frame east in 
halves and securely bolted together. The driving shafts 




Fig. 388. 

are of steel, and the latter drives the slides through short 
connecting rods. The slides have large rectangular bear- 
ing surfaces, those for the punch and the shears being 
fitted with stop motions. 



494 MACHINE SHOP PRACTICE 

Tnis machine is double-geared, and the puneh and shear 
are operated by levers which allow them to remain at the 
top of the stroke during a full one-half revolution of the 
main shaft, thus affording plenty of time for adjustment 
of the plate. 



Fig. 389. 

A is the frame, B the belt-shifter rod, C the fast and 
lo-.se pulleys, D one of the fly-wheels, E belt-shifter forks, 
T and L the belt-shifter brackets, G the belt-shifter lever, 
H the belt-shifter hand-lever, M the belt-shifter lever shaft- 
bracket, and S and P the shear and punch respectively. 



AUXILIARY MACHINE TOOLS 



495 



The single-ended punch and shear shown in Fig. 389 
will punch a five-eighths inch hole in five-eighths iron or 
cut off flat iron one-half inch thick by six inches wide, 
and round iron one and one-eighth inch diameter. 

The cam shaft is made of special hammered steel, with a 
bearing on each side of the cam. The clutches are steel 
faced. 




Fig. 390. 



The tight and loose pulle3?s are fourteen inches in diam- 
eter for three and three-fourths inch belt, and make 180 
revolutions per minute. 

The machine is furnished with one punch, one steel 
socket to fit the slide, one die, one die holder, one die 
block and wrenches. 

Another form of single-ended punch and shear is shown 
in Fig. 390. 



496 



MACHINE SHOP PRACTICE 



Screw Shaving Machine. Fig. 391 illustrates a screw 
shaving machine. 

The draw-back collets are opened and closed in the 
spindle by a hand lever and are invaluable for holding ac- 
curately work of a circular cross section that must be so 
finished that external and internal surfaces shall be con- 
centric. 




Fig. 391. 

The cross rest has two tool posts, operated by a lever, 
pinion and rack. 

Each machine is furnished with spring collets, cross rest, 
oil pump, pan, tank and countershaft. 

Screw Threading Die Holder. A screw threading die 
holder is illustrated in Fig. 392. 

The die is made from a special tool steel, and accurately 
cut, it is made adjusted by a clamping collar. The dies can 
be readily sharpened on an emery wheel. 



AUXILIARY MACHINE TOOLS 



497 



The clamping collar is arranged with a set-screw for 
each prong of the die, thus giving an independent adjust- 
ment. 




The die holder can also be used for holding taps when 
required. The shank of the holder revolves in a sleeve 



498 



MACHINE SHOP PRACTICE 



which has its ends formed into right and left-hand clutches, 
which engage with projections on the shank and head of 
the die holder. This allows the die or tap to remain sta- 
tionary at the instant of reversing the motion, so that it 
may be backed off of the work without jar or danger of 
being broken. The work may be cut close up to a shoul- 
der, or the top be sent to an exact or unvarying depth. 




Pig. 393. 

Valve Milling Machine. Fig. 393 represents a Valve 
Milling Machine, which has been designed with especial 
reference to the requirements of the brass-finishing trade, 
for milling the square or hexagon parts of valve bodies, 
nuts, caps, and oilers. 

The heads are adjusted independently by hand-wheels at 
either end of the bed, so that the cutters may be separated. 



AUXILIARY MACHINE TOOLS 499 

The spindles are hollow, made from special hammered 
steel, accurately ground, and have provisions for taking 
up the wear. 

The upright spindle has three and one-half inch vertical 
adjustment, which is sufficient to always bring the center 
of spindle opposite the center of the work, thus keeping 
the support close to the cutters, and thereby insuring 
smooth work. 

The indexes can be set for either square or hexagon 
milling, as desired, and cannot be set wrong. 

The piece to be milled is held secure with the upright 
spindle, as shown in the cut, by means of the large hand- 
wheel at the lower end of the same. 

When two sides have been milled the article is rotated 
through 60 or 90 degrees by means of the lever shown, 
which, with one motion, unlocks, rotates, and again locks 
the spindle. 



, 1 



PORTABLE TOOLS 



501 



Boring Bar. This 
tool, shown in Fig. 394, 
is useful for boring en- 
gine cylinders without 
detaching them from 
their beds. It may be 
set at any angle or in 
any position. It is also 
useful for boring cylin- 
ders of large diameter 
or great length in the 
lathe or on a table or 
face-plate made for the 
purpose. The cutting- 
tool is attached to a 
sleeve which is moved 
along the bar by means 
of a feed-screw within 
the bar which may be 
operated by the small 
handle shown at the 
left hand end of the bar 
or automatically by the 
pin wheel shown im- 
mediately behind the 
handle. 

Chain Hoists. A two- 
sheave chain hoist of 
the Weston differential 
type is shown in Fig. 
395. This hoist will 




503 



504 



MACHINE SHOP PRACTICE 



sustain the load in any position. A compound worm gear and 
pinion chain hoist is illustrated in Fig. 396. This form of 
hoist is intended for raising heavy loads and is in conse- 
quence very slow in its action. 





Fig. 395. 



Fig. 396. 



Electric Motor. When a source of electricity is near at 
hand, a portable electric motor with a flexible shaft drive 
will be found an excellent method of operating a drill 



PORTABLE TOOLS 



505 



press such as is described in Fig. 397. The illustration 
in Fig. 397 shows plainly the manner in which the motor 
and flexible shaft are connected to the drill press. 




Fig. 397. 



Hand Drill Press. For drilling holes in large castings 
such as the bed-plates of engines, which are of too large 
dimensions to go under a drill press even of large swing. 
The portable drill shown in Fig. 39S is a very handy tool. 
It may be clamped to any part of the casting and be ad- 
justed to almost any position. 

Forge. The forge shown in Fig. 399 has a strong, posi- 
tive, regular blast. It is constructed from structural steel, 
making it strong, stiff and light. The machinery is all en- 
closed in an oil-tight casing, and entirely noiseless. It has 
no belts or friction. It is fitted up throughout with ball 
bearings. 



506 



MACHINE SHOP PRACTICE 





PORTABLE TOOLS 



507 




Fig. 4C0. 

Key Seating Machine. A portable key seating machine 
for use in cutting keyways in shafting when in place, is 
shown in Fig. 400. It has both hand and automatic feed. 



MISCELLANEOUS TOOLS 



509 



r • 




510 



Slide Rests. The construction o.f. a slide-rest may be 
understood from Fig. 401. The cutting tool is carried in 
the upper slide, which, by means of a screw whose handle 
is shown, may be moved in or out on the lower slide so 







Fig. 401. 

as to regulate the depth of the cut taken on 2 the work and 
thus regulate its diameter. To carry the cut along the 
work the upper handle operates a screw whose nut is at- 
tached to the lower slide, and thus traverses the tool along 

the work. 

511 



512 



MACHINE SHOP PRACTICE 



The upper view in Fig. 402' shows a plain slide rest with 
a swivel attachment by which it may be set to any de- 
sired angle. The lower view shows a slide rest with a 
screw cutting attachment. 



fli 





Fig. 402. 

Tool Holders. The tool holders shown in Fig. 403 are 
for boring tools which may be adapted to a variety of pur- 
poses. 



MISCELLANEOUS TOOLS 






OF STEEL 




Fig. 403. 



Fig. 404 shows two cutting-off tools with holders. 
Thread cutting tools are shown in the two views in Fk, 
405. 

Tapping Attachment. Fig. 406 illustrates various forms 
of an Automatic Reverse Tapping Attachment, which is a 
well-designed, double-clutch, quick-reverse mechanism of 
compact and rigid construction. It is attached to and 
aligned with any machine spindle by the regular taper 
shank, and is fitted with a quick change drilling and tap- 



514 MACHINE SHOP PRACTICE 




Fig. 404. 




Fig. 405. 



MISCELLANEOUS TOOLS 



515 



ping chuck, having two sets of jaws to grip both the round 
and the square parts of the tap, which hold standard taps 
and straight or taper shank drills within the range speci- 







fied. The gear train consists of steel spur gears through- 
out, and parts exposed to wear are hardened and bushed. 



516 



MACHINE SHOP PRACTICE 



Style A. Where the work is easily handled and centers 
itself to the top. Work that is drilled and then rehandled 
and tapped. 

Style B. For radial drill work, tapping in surfaces at 
different heights or wherever a stop collar on machine is 
undesirable, it avoids lifting work when disengaging 
clutches. 




Fig. 407. 



Style C. Wherever there is danger of breaking taps by 
the depth of the hole in the metal, as several cuts can be 
taken, it permits the tap to strike the bottom of the hole 
without breakage. 



MISCELLANEOUS TOOLS 517 

Style D. Wherever the work is clamped down, or is too 
heavy to center itself to the tap, the interchangeable tool 
holders are required to drill, tap and set studs, in line 
without stopping or reversing the machine or moving the 
work. 

Hand and Follower Rests. Various forms of hand and 
follower rests are shown in Fig. 407. 

Wet Tool Grinder. The tool grinder shown in Fig. 408 
is a simple and effective machine which is always ready, 
efficient and reliable. By a new and simple device an even, 
steady flow of water can be obtained upon the wheel when 
it is running, and this flow can be regulated to the desired 
amount. The bowl is of generous dimensions, both in front 
and on the sides, and the bearings are dirt-proof and self- 
oiling. 

Countershafts. The countershaft shown in Fig. 409 is 
thrown into action by a pull on the cord attached to the 
weighted lever, which is set in a bearing with just enough 
eccentricity to throw the friction disc into engagement 
with the driven pulley or cone. To stop, another pull on 
the cord sets the lever back to its original position, dis- 
engages the friction, and draws it back enough to entirely 
clear, thus preventing any wear. The weight is propor- 
tioned to hold the friction well in place without undue 
pressure, and the contact roller is made of sufficient size 
so that it runs comparatively slow. It does not run when 
the clutch is out. Allowance is made for taking up any 
wear, so that the weighted lever will always act at the 
best angle and give the proper throw to the eccentric. 

The shaft is stationary in the hanger and the pulleys 
revolve upon it, thus giving them a long bearing. The 
shaft is drilled longitudinally from both ends, and grooved 
to distribute the lubrication, which is effected by a wick. 
The contact roller also revolves upon its shaft and is lubri- 
cated in like manner. 



518 



MACHINE SHOP PRACTICE 




Fig. 408. 



MISCELLANEOUS TOOLS 519 




Fig. 410. 



520 



MACHINE SHOP PRACTICE 



Another form of countershaft is illustrated in Fig. 410. 
This has tight and loose pulleys instead of friction clutches, 
but in operation is very similar to the one shown in Fig. 
409. 




Fig. 411. 

Magnetic Chuck. The illustration shown in Fig. 411 
shows the special rotary magnetic chuck for grinding the 
sides of discs and washers. They are made in two sizes, 
10 inches and 12% inches diameter respectively. The draw- 
ing shows the 10 inch size, and the washers shown are l 1 /^ 
inch diameter approximately. It will be seen that this 
is a sixteen to one proposition compared to finishing one 
washer at a time. In these chucks the magnetic force is 

concentrated im- 
mediately under the 
work and a slightly 
projecting rim main- 
tains the work con- 
centric with the 
Fig. 412. ~"^^.F" tr- chuck. 

A magnetic vise for use on milling machines, surface 
grinders and other tools where small pieces require to be 




MISCELLANEOUS TOOLS 



521 



held firmly and yet frequently to be changed around to pre- 
sent a fresh surface for milling' or grinding-, is shown in 
Fig. 412. 





Fig. 413. 



Demagnetizes Hardened cast steel, and to a slight de- 
gree cast iron, coming in contact with a magnetic chuck, 
becomes permanently magnetized. On some classes of work 
this is objectionable and the apparatus shown in Fig. 413 
is the outcome of a long series of experiments to overcome 
this difficulty. The apparatus has proven an entire sue' 



522 MACHINE SHOP PRACTICE 

cess, instantly removing all traces of magnetism by simply 
vibrating the work several times over the top of the ap- 
paratus. 

This apparatus consists of a finely finished quartered 
oak box on an iron base to which are attached the boxes 
for the revolving magnet, the pulley for which is shown 
at the right. The cover of this apparatus is detachable and 
supports a mass of laminated plates of thin sheet metal 
attached to the two top plates shown in the cut. The work 
to be demagnetized is laid across the top plates and lifted 
away and lowered again. This apparatus has the effect of 
alternating the polarity of the work which leaves behind a 
portion of its magnetic charge each time it is withdrawn 
out of the magnetic field. Wires lead from the left-hand 
end of the demagnetizer to the countershaft shown in Fig. 
413, in which both the starting and stopping is done by 
pulling a cord, and in which the movement of the shipper 
operates an electric switch automatically to supply the 
demagnetizer, and in stopping automatically cuts cut the 
current. 

Customers who prefer to furnish their own count* '•shaft, 
can do so and operate the electric circuit separately by an 
ordinary switch placed in the circuit, first, however start- 
ing the apparatus in motion. 



PLAIN AND SPIRAL 
INDEXING DEVICES 



523 



Plain Index Center. The Index Center shown in Fig. 414 
is made in two sizes. The spindle is 2% inches in diameter 
and is made tapering so as to compensate for wear. The 
nose is threaded to receive a chuck or any other fixture. 
The divisions are made with a single notched plate which 
can be handled very rapidly. Three plates can be carried 
on the spindle, so that a variety of divisions can be made 
without removing a plate. After the division is made, t T ie 




Pig. 414. 



spindle can be securely locked in position with the small 
lever shown at the side. This takes all the strain off the 
index mechanism. The plates are a plain lathe job and 
can be easily duplicated and cut any number of divisions 
required. 

Differential Indexing Device. Differential Indexing is 
accomplished by gearing the spindle to the index plate. It 
is much simpler than the compound method and covers a 
much larger range than it is practicable to obtain S)y 

525 



526 



MACHINE SHOP PRACTICE 



special index plates. With it all prime numbers within 
the range of gear cutting can be obtained. Owing to its 
simplicity the liability of error is very small, one circle 
of holes is used the same as in plain indexing. The index 
handle being turned in one direction only, the differential 
feature is obtained by gears in a positive manner. 

Fig. 415 shows a Differential Indexing device. The 
quadrant carrying the change gears, swivels on the bevel 
bracket. The quadrant is split and is clamped in any re- 
quired position upon the bracket, thereby providing an 




Fig. 415. 

easy arid substantial method for properly meshing the gears. 
The back of the head spindle is bored taper, keywayed, and 
carries a change gear stud. The connection from this stud 
to the worm shaft is made by the quadrant which has two 
T-slots in it for properly adjusting and carrying both the 
compounds and idlers. As the whole arrangement is self- 
contained, the head can be placed in any position on the 
table. The change gears and index-plates furnished, cover 
all numbers to 360. 

Universal Head. The drawing shown in Fig. 416 is a 
Universal Dividing Head. As its name signifies it is a uni- 
versal head in all respects, all kinds of dividing, at any 
angle, or spirals of any form, can be cut on it. The swivel 
can be turned completely over from one side to the other, 
and to 10 degrees below the horizontal on either side, de- 






INDEXING DEVICES 52*7 

scribing an arc of 200 degrees. It is not necessary to re- 
move any part of the head to secure this range. 

The main body or swivel of the head is one solid cast- 
ing, bored and turned to receive the different parts. It 
is completely circular in form except the part at the main 
spindle. This is cut back so as to allow as great a distance 
as possible between the centers and reduce the height when 
set in a vertical position. A dovetail is turned completely 




Fig. 416. 

around the swivel for clamping it to the base. The base 
is accurately turned to fit the swivel, both ends and the 
main body of the swivel forming a bearing which is 
securely clamped to the base by clamping bolts, the heads 
of these being turned the exact radius of the dovetail in 
the swivel. 

Universal Spiral Cutting Head. Fig. 417 shows a uni- 
versal head, designed especially for heavy spiral work, it 
having all the advantages of a spiral combined with the 
features of a universal head. 

The spindle can be swung through an arc of 110 degrees,, 
which is ample for cutting bevel gears or work of this de- 
scription. The spindle is very large, and is made of ham- 
mered crucible steel. It can be quickly clamped in any 



528 



MACHINE SHOP PRACTICE 



position, relieving the worm and worm wheel from all 
strain when taking a heavy cut. 

The dividing worm is placed near the front of the spin- 
dle, this construction allows of a much greater diameter of 
worm wheel than in any other style of head. It is cut 
with a special geared fixture, insuring great accuracy. 
With the index plates furnished, all numbers to 50, the 




Fig. 417. 

even numbers to 100, and most numbers to 360, can be 
divided. When required the worm can be disengaged from 
the worm wheel and the spindle revolved by hand. This 
can be done quickly without removing any part of the head, 
and can be instantly readjusted to a positive stop. When 
the spindle is released the divisions can be made with 
front plate by an index pin. Is very handy for reamers, 
milling cutters, taps, hexes, squares and work of this char- 
acter. 

The front end of the spindle is threaded for a chuck. 
Tne up and down adjustment of the center is obtained by 
a screw so that it can be set accurately and can be clamped 
securely in any position. 



NOTES ON THE WORKING OF STEEL 



829 



Steel. Steel is a compound of iron and carbon, varying 
in proportion of 0.5 per cent to 5 per cent of carbon. Spe- 
cific gravity 7.8, tensile strength from 90,000 to 120,000 
pounds per square inch. Ordinary steel is carbon steel, 
but steely compounds of iron have been produced which 
have the same general properties as ordinary steel, the car- 
bon of which is replaced by other chemical elements. 

To test steel and iron. Nitric acid will produce a black 
spot on steel, the darker the spot, the harder the steel. 
Iron, on the contrary, remains bright if touched with nitric 
acid. Good steel in its soft state has a curved fracture 
and a uniform gray lustre, in its hard state a dull, silvery, 
uniform white. Cracks, threads or sparkling particles de- 
note bad quality. 

Good steel will not bear a white heat without falling to 
pieces, and will crumble under the hammer at a bright red 
heat, while at a mild red heat it may be drawn out under 
the hammer to a fine point. 

Case Hardening. Place horn, hoof, bonedust or shreds of 
leather, together with the article to be case hardened, in an 
iron box subject to a blood-red heat, then immerse the 
article in cold water. 

Case Hardening with Prussiate of Potash. Heat the 
article after polishing, to a bright red, rub the surface over 
with prussiate of potash. Allow it to cool to a dull red, 
and immerse it in water. 

Case-Hardening Mixtures. Three parts prussiate of pot- 
ash and 1 part of sal-ammoniac, or, 1 part of prussiate of 
potash and 2 parts of sal-ammoniac or, bone-dust alone. 

A good soft heat is safe to use if steel be immediately 
and thoroughly worked. It is a fact that good steel will 
endure more pounding than any iron. 

531 



532 MACHINE SHOP PRACTICE 

If steel be left long in the fire it will lose its steely 
nature and grain, and partake of the nature of cast iron. 
Steel should never be kept hot any longer than is necessary 
for the work to be done. 

Steel is entirely mercurial under the action of heat, 
and a careful study will show that there must of necessity 
be an injurious internal strain created whenever two or 
more parts of the same piece are subjected to different 
temperatures. 

It follows that when steel has been subjected to heat 
not absolutely uniform over the whole mass, careful an- 
nealing should be resorted to. 

As the change of volume due to a degree of heat in- 
creases directly and rapidly with the quantity of carbon 
present, high carbon steel is more liable to dangerous in- 
ternal strains than low carbon steel, and great care should 
be exercised in the use of high carbon steel. 

Hot steel should always be put in a perfectly dry place 
of even temperature while cooling. A wet place in the floor 
might be sufficient to cause serious injury. 

Never let anyone fool you with the statement that his 
steel possesses a peculiar property which enables it to be 
" restored' ' after being ''burned"; no more should you 
waste any money on nostrums for restoring burned steel. 
For "burned" steel, which is oxidized steel, there is only 
one way of restoration and that is through the knobbling 
fire or blast furnace. "Overheating" and "restoring" 
should only be allowable for purposes of experiment. The 
process is one of disintegration, and is always injurious. 

Be careful not to overdo the annealing process; if carried 
too far it does great harm, and it is one of the commonest 
modes of destruction which the steel maker meets in his 
daily troubles. It is hard to induce the average worker in 
steel to believe that very little annealing is necessary, and 
that a very little is really more efficacious than a great 
deal. 



NOTES ON STEEL 533 

Experiments show conclusively: That the breaking strain 
of iron and steel does not (as hitherto assumed) indicate 
the quality. A high-breaking strain may be due to hard, 
unyielding character, or a low one may be due to extreme 
softness. The contraction of area at the fracture forms an 
essential element in estimating the quality. 

Iron when fractured suddenly produces a crystalline frac- 
ture, but if gradually, a fibrous fracture. This accounts for 
the anomaly in the supposed change of iron from a fibrous 
to a crystalline character. Sudden shoulders which pre- 
vent a regular elongation of fibre cause a sudden snap. 

The strength of steel is reduced by being hardened in 
water, but both its hardness and toughness are increased 
by being hardened in oil. Iron heated and suddenly cooled 
in water is hardened, and the beaking strain, if gradually 
applied, is increased, but it is more likely to snap suddenly. 
It is softened and its breaking strain reduced if heated 
and allowed to cool gradually. Iron if brought to a white 
heat is injured if it be not at the same time hammered 
or rolled. Case-hardening bolts weakens them. 

Hardening and Tempering Steel. To one gallon of com- 
mon fish or whale oil, take one pound each of beeswax and 
resin. Put into a kettle and heat till it comes to a boiling 
point, stirring it once in a while. When thoroughly mixed 
it is ready for use. 

To harden in this solution, heat the steel till the scale 
rises a little, then immerse in the oil. Wlhen cool, heat 
over a clean fire till cherry red in the dark. 

The foregoing, with a little practice, is recommended as 
one of the best, if not the best, compositions for hardening 
steel tools for use in cutting iron or wood, or even steel. 
Care must be taken as to the amount of resin in the oil, 
as resin hardens the steel, whereas beeswax and tallow 
toughen it. If a person prefer to temper in daylight, clean 
the steel or tool, polish- it, and draw to a deep straw color, 



534 MACHINE SHOP PRACTICE 

if for cutting iron or steel, and purple if for wood cutting 
tools. 

To Prevent Blow-Holes in Steel. To prevent blow-holes 
in cast steel, add to fluid steel an alloy of aluminum with 
a metal of the alkali earth group, or with lithium. Alu- 
minum alone does not act upon the nitrogen and hydrogen 
in the fluid metal. The metals of the alkaline earths and 
lithium possess that property, but they are too dear for 
commercial use alone. An alloy of aluminum and calcium 
gives the effect of each element, so that the carbon mon- 
oxide and also the nitrogen and hydrogen can be removed. 

Notes on Steel. In annealing cold rolled steel, gas is 
turned into the annealing boxes after they are removed 
from the furnace. The burning of the gas uses up any air 
that might come in contact with the steel while cooling. 
By this method the steel comes out of the boxes in bright 
condition. ' 

Where a defect occurs in a finished article made of steel, 
and always in the same place, the steel is not at fault; 
there is something wrong with the method of making the 
article. 

The tempering heat is not so high as the annealing heat; 
the annealing heat is not so high as the hardening heat, 
and the hardening heat is lower than the forging heat. 
Always, in practice, bear this in mind. The only exception 
is in the case of high-speed steel, which is a law unto 
itself. 

Twist drills hardened in a water bath should be plunged 
deep enough to harden a short distance on the shank. 
Water cracks are apt to occur if the drills are held almost 
stationary in the water. If the drills are soft directly 
back of the water cracks, it is proof that this portion was 
held at the water line or so close to it that they did not 
go into the bath deep enough to harden. 

High speed or self-hardening steel, when required to be 
cut or broken off into tool lengths,., should first be nicked 






NOTES ON STEEL 535 

deeply in the bar while hot, or better, should be cut en- 
tirely through. Cracks and slivers are liable to be pro- 
duced if nicked but slightly. 

Case-Hardening Wrought Iron. It may not be generally 
known that the case-hardening of iron parts means the 
partial conversion of the outer surface into steel. The 
most common method of case-hardening is to place the 
pieces in an iron case in company with either bone-ash, 
leather or horn cuttings. The high quality and depth of 
the steel case amply repay for the extra initial cost, taking 
care that no two pieces are in contact, and carefully luting 
all the joints between the lid and sides with fireclay or 
loam, to exclude the air, and heating to redness in a fur- 
nace for a time varying with the number and size of the 
pieces. 

Bone-ash is the cheapest, as it can be used over and 
over again by adding new bone to the mass and mixing 
thoroughly each time the box is charged. 

Tempering Tool Steel. The following table gives the 
temperature in degrees Fahrenheit necessary to produce the 
required color, when tempering hardened steel. 
Lathe, Shaper and Planer tools: 

430° Very light straw color. 
450° Light straw color. 
Taps, Dies and Wood turning tools: 
470° Dark straw color. 
490° Very dark straw color. 
Hatchets, Chisels, etc: 

500° Brownish yellow. 
520° Yellow tinged with purple. 
530° Light purple. 
Springs, etc.: 

550° Dark purple. 
570° Dark blue. 
Proportional parts of Lead to 1 pound of pure Block Tin, 
which when melted will have the temperature in degrees 



536 



MACHINE SHOP PRACTICE 



Fahrenheit, necessary to produce the required color on 
hardened steel, by simple immersion. 



Color. Temperature. 

Very light straw color 430° 

Light straw color 450° 

Dark straw color 470° 

Very dark straw color 490° 

Brownish yellow 500° 

Light purple 530° 

Dark purple 550° 

Dark blue 570° 



Pounds of 


Lead to 


one of Tin. 


1% 


to 1 


2% 


to 1 


2% 


to 1 


3% 


to 1 


43/4 to 1 


7% 


to 1 


12 


to 1 


25 


to 1 



GAS FURNACES 



537 



Gas is not the cheapest fuel, but no other kind of fuel 
can be used to such advantage in manufacturing processes 
which require precision in the use of heat. This statement 
is confirmed by an experience of over twenty years in the 
utilization of gas in mechanical heating processes. 

The appliances illustrated herewith form part of a fuel 
gas system, which owes its inception to a crucible furnace 
originally made in France, on the principle of the Bunsen 
Burner, depending for induction of the air required for 
combustion upon the pressure of the gas supply aided by 
natural draft. This furnace proved wasteful of gas and 
too slow in operation, to be profitable for manufacturing 
purposes. 

Efforts to improve upon this furnace suggested that the 
respective functions of gas and air be reversed, and in the 
system devised a positive air blast inducts the gas, which 
is injected into the combustion chamber as a properly pro- 
portioned mixture of both under controllable positive pres- 
sure. 

The success attending the introduction of crucible fur- 
naces embodying this principle has resulted in its appli- 
cation to a great variety of heating devices, whose size was 
limited by the cost of gas. 

Gas furnaces fulfill their purpose if they contribute mate- 
rially towards the excellences and uniformity of the product 
and lessen its total cost. The single item of fuel cost may 
be increased or diminished by the use of gas, but this is 
of secondary importance in considering their introduction. 
An increased fuel account is amply compensated for, and 
its decrease merelv an incidental advantage. 

539 



540 MACHINE SHOP PRACTICE 

The fuel nearest perfection is gas, and of all fuel gases 
naphtha gas has been found the best and also the cheapest, 
when measured by net results. 

Oil Tempering Furnace. For small work a wire basket is 
used in the tempering furnace shown in Fig. 418, and 
larger work is suspended in the bath in any convenient 
way. The temperature being under control of the gas and 




Fig. 418. 

air valves, the bath is heated until the thermometer shows 
the proper heat. When the work is submerged in the bath 
it cools down and the work remains there until the tem- 
perature rises again to the proper degree for the temper 
wanted, and is then removed. 

Bench Forge. The furnace shown in Fig. 419 is a handy 
little gas forge, to be placed on the work bench, for forg- 
ing and tempering small tools, heating the ends of rods or 



GAS FURNACES 



541 



small pieces of metal of any kind. The heating space or 
chamber is one and one-half inches wide and high, and 
three inches deep, heated evenly throughout by two side 
burners whose focus is the center of the slot. Work can 




Pig. 419. 



be placed over the slot and heated from below, or the slot 
can be covered by a slab shown in the cut, and the heat 
confined to the chamber and raised to a very high degree 
quickly. 



542 



MACHINE SHOP PRACTICE 



Twist Drill Hardening Furnace. A furnace for the proper 
hardening and tempering of twist drills and reamers is 
shown in Fig. 420. 




Fig. 420. 



Tool Room Forge. Fig. 421 shows a tool room forge for 
the tempering of cutting tools. 

Positive Pressure Blower. A positive pressure blower for 
use in connection with the gas heating furnace is shown in 
Figs. 422 and 423. 



GAS FURNACES 



543 




Fig. 421. 



544 MACHINE SHOP PRACTICE 




Pig. 422. 



GAS FURNACES 



545 




Fig. 423. 



SHOP TALKS 



547 



Be a, mechanic, not a machine. Stay at home evenings 
and study natural philosophy, chemistry, mathematics, 
drawing, etc. Fit yourself for a high position. Save your 
money and go to a technical school. Choose one branch of 
mechanical art and study it and learn all you can about it. 
Yon will find little trouble in getting a good paying job. 

Eemember that water never rises higher than its head, 
or its fountain, neither can you rise higher than your aim 
or ambition in life. 

Every mechanic should thoroughly understand natural 
philosophy. It is as necessary in every day life as a 
knowledge of arithmetic. No matter what trade you may 
choose you will find it a great help to you. Many things 
that it would be impossible to comprehend without it, will 
be readily understood with it. 

Learn a trade, study it and learn it thoroughly. Learn 
to mind your own business and let other people's business 
alone. 

The Almighty 7 has little use for a lazy man or woman 
in this world, and not likely any use for them in the next. 

Never say you Can't because you have nobody to help 
you. God helps those that help themselves. 

Are you willing to say you cannot do what is being done 
by others? Are you willing that others should outrun you 
in the great race of life? Are you willing to be left far 
behind, to be the fag-end of humanity? To leave this world 
unknown, uncared for, forgotten? Are you willing to die 
and to leave no void, to have it said that this world is as 
well off without you as with you? 

Hoe your own row. Ask no favors, learn to rely upon 
yourself. Learn to fight your own battles, and to fight 
them manfully. 

God has placed the whole world before you and told you 
to subdue or conquer it. He has given you life, health, 

549 



550 MACHINE, SHOP PRACTICE 

strength, and vigor of youth. He has done all that is pos- 
sible for Him to do for you, and now it is your fault if 
you do not get your share of this world. 

Fit up a nice place in your house for your boys. Put in 
a work bench and some good tools, it will keep them at 
home, besides it will learn them to make many a handy 
thing about the house. It is the best investment you can 
make for them. 

God expects you to climb up higher than your father and 
mother. He expects you to take their good qualities and 
improve on them. 

How to Make a Good Weld. For a good weld have the 
tuyere iron from four to eight inches under. In other words, 
have four to eight inches of coal on the tuyere iron de- 
pending upon the character of the work being done. Coke 
the coal and beat it down solidly around the fire. Now 
beat the iron to the welding point, then upset and scarf. 
In order to make the most perfect welds, scarf the iron 
properly. Upset well to allow for wasting away. Have the 
scarf full in the center, so that the two pieces to be joined 
will touch in the center first. If there is a hollow in the 
center, foreign substances are liable to collect in there and 
cause a very imperfect weld. When they have reached a 
good, clean, white heat with the scarf down in the fire, 
take them out and give each one a good jar on the anvil 
while the scarf is still down, so as to jar off any dirt which 
may be on them. Reverse or turn over the one in the left 
hand, get them together as quickly as possible and hammer 
rapidly so as to get them united before the heat gets below 
the welding point. The cold anvil will reduce the heat be- 
low the welding point in a very short space of time. Don't 
be continually poking at the fire. Let the clinkers gather 
at the bottom. 

A welding trick is given as follows: The way to go 
about it is first to be sure that the fire is perfectly clean, 
and then to take the heats very carefully, getting as good 



SHOP TALKS 551 

and as even an heat as possible without overheating the 
steel. After proceeding in this way, and using borax only 
for a flux, if it is not successful try mixing some, fine bor- 
ings with the borax and covering the weld with this. Borax 
and fine steel borings from a drill are a splendid compound 
for steel welding. 

How to Manage a Foundry. 

If a foundry foreman desires to keep his shop up to a 
high state of efficiency, he will, as soon as he receives an 
order for castings, see that the necessary cores are at once 
ordered from the core department. Then he will proceed 
to learn if he has a suitable flask for the casting, and if he 
has, he will ascertain if any repair work be needed on this, 
and, if so, he will have this done before the flask is taken 
to the molder 's floor. All repairing of flasks should be 
done by a flask man instead of by the molder and his 
helper. 

In order that the molder may use his time to the best 
advantage, the helper should see that he not only has his 
facing sand, gaggers, clamps, handy, but he should also 
look after the many little things which the molder some- 
times spends his high-priced time in looking up. Even in 
specialty shops molders take a hand in barring up flasks. 
This they should not have to do as this kind of labor be- 
longs to the flaskmaker and the latter will do a better job 
than the molder every time. 

In a great many foundries the men depend too much 
upon the foreman for everything. They should remember 
that he is only human, and has not the time to attend to 
every little detail. It has always seemed strange, too, that 
the place where castings are made should receive so little 
attention from the owners of plants, as majority of whom 
seem to think that anything can be made to do for this 
department. Perhaps nearly every practical foreman is 
familiar with shops where ordinary equipment is so scarce 



552 MACHINE SHOP PRACTICE 

that the molders are spending a great part of their time 
looking for things of which each should have a plentiful 
supply. The successful foundry manager of to-day must 
not only be a practical molder, but also experienced in 
cupola practice, or he is not fully equipped for the position. 
Cutting Left-Hand Threads with Right-Hand Tools. 

The dies are opened sufficiently to admit a right-hand 
tap of the desired lead, and the rod to be threaded. The 
rod is backed up by a piece of annealed copper into which 
the threads may imbed themselves without injury. The die 
should be of the same lead as the tap, which permits the 
tap being accurately meshed with its thread. With this 
combination it is claimed that a fair left-hand thread may 
be cut with the ordinary right-hand equipment. 

Boring an Engine Cylinder. A 10 or 12-horsepower 
stationary engine cylinder may be bored on a 24-inch lathe 
even if cast iron brackets and adjusting screws are not 
handy. Get four good seasoned oak pieces, long enough to 
reach across the lathe carriage. Bore holes for the bolts, 
which should fit the T slots in the carriage. Find the 
radius of outside diameter of the cylinder. Lay blocks in 
the carriage. Take a pair of dividers, set them to the 
radius of the cylinder and scribe from the lathe center on 
blocks and cut out. Get four % or %-inch bolts, long 
enough to allow the nuts to have a full thread after the 
top clamp is on. Next place the bar through the cylinder 
and between the lathe centers, put the tool in the bar, 
tighten it just enough to hold it in place, true the cylinder 
by counter lines, on each end turning the bar by hand. If 
too low when tightened down, loosen up and raise with 
pasteboard under the blocks on the carriage. After getting 
the cylinder perfectly true set the tool to take just enough 
out to true the inside by taking a roughing cut and finish- 
ing cut. Run the lathe on slow speed, and feed just fine 
enough to make a smooth job. Never stop the lathe while 
taking the finishing cut. 



SHOP KINKS 



553 



Glue. A little powdered chalk added to common glue 
makes it much stronger. A glue that will resist the action 
of water may be made by using skimmed milk instead of 
water. 

Drilling Glass. Glass can be drilled with a common drill 
very readily, by using a mixture of turpentine and camphor. 
When the point of the drill has come through, it should 
be taken out and the hole worked through with the point 
of a three-cornered file, having the edges ground sharp. 
Use the corners of the file, and scraping the glass, rather 
than using the file as a reamer. Great care must be taken 
not to crack the glass or flake off parts of it in finishing 
the hole after the point of the drill has come through. Use 
the mixture freely during the drilling and scraping. The 
above mixture Avill be found very useful in drilling hard 
cast iron. Tempered steel can be drilled by making the 
drill very hard and using this mixture. 

Drilling Malleable Iron. Use kerosene oil to drill, ream or 
turn Malleable Iron. It will make the work much 
smoother. 

Drilling Hard Steel. Use turpentine instead of oil when 
drilling hard steel, saw plate, etc. It will drill readily 
when you could not touch it with oil. 

Drilling Aluminum. Use kerosene oil for drilling or 
turning aluminum. 

Tinning Surfaces. Articles of brass or copper boiled in 
a solution of cyanide of potassium mixed with turnings or 
scraps of tin in a few moments become covered with a 
firmly attached layer of fine tin. 

A similar effect is produced by boiling the articles with 
tin turnings or scraps and caustic alkali, or cream of tar- 
tar. In either way, articles made of copper or brass may 
be easily and perfectly tinned. 

555 



556 MACHINE SHOP PRACTICE 

Sharpening Files. To sharpen dull and worn out files, lay 
them in dilute Sulphuric Acid, one part acid to two parts 
of water over night, then rinse well in clear water, put the 
acid in an earthenware vessel. 

Rust Joint Composition. This is a cement made of sal- 
ammoniac 1 pound, sulphur y 2 pound, cast-iron turnings 
100 pounds. The whole should be thoroughly mixed and 
moistened with a little water. If the joint is required to 
set very quick, add ^ pound more sal-ammoniac. Care 
should be taken not to use too much sal-ammoniac, or the 
mixture will become rotten. 

Soldering Aluminum. Small surfaces of aluminum can 
be soldered by the use of zinc and Venetian turpentine. 
Place the solder upon the metal together with the turpen- 
tine and heat very gently with a blowpipe until the solder 
is entirely melted. The trouble with this, as with other 
solders, is that it will not flow gently on the metal. There- 
fore large surfaces cannot be easily soldered. 

Another method is to clean the aluminum surfaces by 
scraping, and then cover with a layer of paraffine wax as 
a flux. Then coat the surfaces by fusion, with a layer of 
an alloy of zinc, tin and lead, preferably in the following 
proportions: Zinc five parts, tin two parts, lead one part. 

The metallic surfaces thus prepared can be soldered to- 
gether either by means of zinc or cadmium, or alloys of 
aluminum with these metals. In fact, any good soldering 
preparation will answer the purpose. 

A good solder for low-grade work is the following: Tin 
95 parts, bismuth five parts. 

A good flux in all cases is either stearin, vaseline, 
paraffine, copaiva balsam, or benzine. 

In the operation of soldering, small tools made of alu- 
minum are used, which facilitate at the same time the 
fusion of the solder and its adhesion to the previously pre- 
pared surfaces. Tools made of copper or brass must be 



SHOP KINKS 557 

strictly avoided as they would form colored alloys with 
the aluminum and the solder. 

Sweating Aluminum to Other Metals. First coat the alu- 
minum surface to be soldered with a layer of zinc. On top 
of the zinc is melted a layer of an alloy of one part alu- 
minum to two and one-half parts of zinc. The surfaces 
are placed together and heated until the alloy between them 
is liquefied. 

Aluminum Solder. This consists of 28 pounds of block 
tin, three and one-half pounds of lead, seven pounds of 
spelter, and 14 pounds of phosphor-tin. The phosphor-tin 
should contain 10 per cent of phosphorus. Clean off all 
the dirt and grease from the surface of the metal with 
benzine, apply the solder with a copper bit, and when the 
molten solder covers the metal, scratch through the solder 
with a wire scratch brush. 

Annealing Cast Iron. To anneal cast iron, heat it in a 
slow charcoal fire to a dull red heat; then cover it over 
about two inches with fine charcoal, then cover all with 
ashes. Let it lay until cold. Hard cast iron can be softened 
enough in this way to be filed or drilled. This process will 
be exceedingly useful to iron founders, as by this means 
there will be a great saving of expense in making new 
patterns. 

To make a casting of precisely the same size of a broken 
easting without the original patterns: Put the pieces of 
broken casting together and mould them, and cast from 
this mould. Then anneal it as above described; it will ex- 
pand to the original size of the pattern, and there remain 
in that expanded state. 

Metal Patterns. All metal patterns should be thoroughly 
cleaned with a stiff brush, then with a brush having a 
plenty of beeswax in it, dip this brush in powdered plum- 
bago. Brush the pattern well with the above and it will 
draw much better and you will have a much smoother 
casting. 



558 MACHINE SHOP PRACTICE 

Babbit Metal. Put a piece of Rosin, the size of a walnut, 
into Babbit metal, stir thoroughly, then skim. It makes 
Babbit metal run better, and improves it. Babbit metal 
will run in places with the rosin in, where without it it 
would not. It is ajso claimed that rosin will prevent blow- 
ing when pouring it into damp boxes. 

Rust on Tools. To prevent rust on tools use Vaseline, to 
which a small amount of powdered gum camphor has been 
added. Heat together over a slow fire. 

Graphite. Graphite is one of the best lubricants known. 
It largely increases the lubricating quality of any oil or 
grease. 

Liquid Glue. Glue will keep liquid when cold if about 
one-sixth part by volume of acetic acid is added to it. This 
is similar to Spalding's Liquid Glue. 

Pattern Letters. To fasten Pattern Letters on a metal 
pattern use beeswax. Heat the pattern sufficient to melt 
the wax, then place the letters in position and let the pat- 
tern cool. 

To fasten letters on a wood pattern use shellac varnish. 

Moulding Thin Pieces. Many times in an iron foundry 
there are moulds to pour that have small projections or 
very thin places. All such places should be vented with 
a fine wire through the cope. In pouring such moulds 
throw about 1 ounce of lead in a ladle to about 50 pounds 
of iron. 

Testing Solder. Good solder is much easier bought than 
made, but if some distance from a base of supplies, buy 
block tin and cut it up into 1-pound pieces, weigh it and 
put in an equal weight of lead. Melt in a ladle, stir it and 
run it off into a mold to cool. To test solder and find out 
whether it is of good quality, hold it up near the ear and 
bend it. If it cringes or makes a crackling noise, it is 
good, and if not, it is poor— to much lead and not enough 
tin in it. 

Tinning Cast Iron. To successfully coat castings with tin 



SHOP KINKS 559 

they must be absolutely clean and free from sand and 
oxide. They are usually freed from imbedded sand in a 
rattler or tumbling box, which also tends to close the sur- 
face grain and give the article a smooth metallic face. 
The articles should be then placed in a hot pickle of one 
part of sulphuric acid to four parts of water, in which they 
are allowed to remain from one to two hours, or until the 
recesses are free from scale and sand. Spots may be re- 
moved by a scraper or wire brush. The castings are then 
washed in hot water and kept in clean hot water until 
ready to dip. For a flux, dip in a mixture composed of 
four parts of a saturated solution of sal ammoniac in 
water and one part of hydrochloric acid, hot. Then dry 
the castings and dip them in the tin pot. The tin should 
be hot enough to quickly bring the eastings to its own tem- 
perature when perfectly fluid, but not hot enough to 
quickly oxidize the surface of the tin. A sprinkling of 
pulverized sal ammoniac may be made on the surface of 
the tin, or a little tallow or palm oil may be used to clear 
the surface and make the tinned work come out clear. As 
soon as the tin on the castings has chilled or set, they 
should be washed in hot sal soda water and dried in saw- 
dust. 

Alloys for Metal Patterns. An alloy suitable for small 
metal patterns is composed of tin one part and lead one 
part by weight. The result is a somewhat soft alloy which 
requires care in the handling of the patterns. Some harder 
mixtures are as follows: 



L»ead. 


Antimony. 


Tin. 


55 


30 


15 


55 


22.7 


22.3 


61.3 


18.5 


20.7 



A white metal that has small shrinkage and is good for 
pattern plates is lead 90, antimony 10. A harder metal 
with small shrinkage and very good for pattern-plates is 



560 MACHINE SHOP PRACTICE 

zinc 66 per cent, tin 34 per cent. An amalgam, very con- 
venient for stopping up holes that cannot be soldered 
easily, is made of the fillings of the above alloy, and mer- 
cury kneaded in the hand into stiff dough, squeezing out 
all the mercury possible. This amalgam should be pressed, 
when first made, into the cavity and allowed to harden. 
When hard it may be scraped or filed like the metal itself. 

Etching on Iron or Steel. Take one-half ounce of nitric 
acid and one ounce of muriatic acid. Mix, shake well to- 
gether, and it is ready for use. Cover the place you wish 
to mark with melted beeswax, when cold write the inscrip- 
tion plainly in the wax clear to the metal with a sharp 
instrument, then apply the mixed acids with a feather, 
carefully filling each letter. Let it remain from one to 
ten minutes, according to the appearance desired. Then 
throw on water, which stops the etching process and re- 
moves the wax. 

Soldering Solution. An excellent method of preparing 
resin for soldering bright tin is given as follows: Take one 
and one-half pounds of olive oil and one and one-half 
pounds of tallow and 12 ounces of pulverized resin. Mix 
these ingredients and let them boil up. When this mix- 
ture has become cool, add one and three-eighths pints of 
water saturated with pulverized sal ammoniac, stirring 
constantly. 

Softening Cast Iron. To soften iron for drilling, heat 
to a cherry-red, having it lie level in the fire. Then with 
tongs, put on a piece of brimstone, a little less in size than 
the hole is to be. This softens the iron entirely through. 
Let it lie in the fire until cooled, when it is ready to drill. 

Suggestions how to Solder. Clean the parts thoroughly 
from all rust, grease or scale, then wet with prepared acid. 
Hold the soldering copper on each part until the article is 
well tinned and the solder has flowed to all parts. 

Watch-Makers' Oil that Will Never Corrode or Thicken. 
Take a bottle about half full of good olive oil and put in 






SHOP KINKS 561 

thin strips of sheet lead, expose it to the sun for a month, 
then pour off the clear oil. The above is a very cheap way 
of making a first-class oil for any light machinery. 

Varnish for Copper. To protect copper from oxidation 
a varnish may be employed which is composed of carbon 
disulphide 1 part, benzine 1 part, turpentine oil 1 part, 
methyl alcohol 2 parts and hard copal 1 part. It is well 
to apply several coats of it to the copper. 

Glue for Iron. Put an equal amount by weight of finely 
powdered rosin in glue and it will adhere firmly to iron 
or other metal surfaces. 

Soldering or Tinning Acid. Muriatic Acid 1 pound, put 
into it all the zinc it will dissolve and 1 ounce of Sal 
Ammoniac; add as much clear water as you have acid, it is 
then ready for use. 

Plaster of Paris. Common plaster that farmers use to 
put on land and plaster of paris are the same thing, except 
plaster of paris is common plaster calcined. Many times 
it is difficult to get calcined plaster, and when it is pro- 
cured it is badly adulterated with lime and unfit for many 
uses. To calcine plaster, or in other words, to make com- 
mon plaster so it will harden, you have but to take the 
plaster and put it in an iron kettle and place it over a 
slow fire, put no water in it. In a few moments it will be- 
gin to boil and will continue to do so until every particle 
of moisture is evaporated out of it. When it has stopped 
boiling take it off, and when cold it is ready for use. 
Plaster treated in this way will harden much quicker and 
harder than any which can be bought ready prepared. 

Hardening Small Articles. To harden small tools or ar- 
ticles that are likely to warp in hardening, heat very care- 
fully, and insert in a raw potato, then draw the temper as 
usual. 

Bluing Brass. Dissolve one ounce of antimony chloride 
in twenty ounces of water and add three ounces of pure 
hydrochloric acid. Place the warmed brass article into this 



562 MACHINE SHOP PRACTICE 

solution until it has turned blue. Then wash it and dry 
in sawdust. 

Drilling Glass. Take an old three-cornered file, one that 
is worn out will do, break it off and sharpen to a point 
like a drill and place in a carpenter 's brace. Have the 
glass fastened on a good solid table so there will be no 
danger of its breaking. Wet the glass at the point where 
the hole is to be made with the following solution: 

Ammonia 6V2 drachms 

Ether 3^2 drachms 

Turpentine 1 ounce 

Keep the drill wet with the above solution and bore the 
hole part way from each side of the glass. 

Another solution is to dissolve a piece of gum camphor 
the size of a walnut in one ounce of turpentine. 

Another method is to use a steel drill hardened, but not 
drawn. Saturate spirits of turpentine with camphor and 
wet the drill. The drill should be ground with a long point 
and plenty of clearance. Run the drill fast and with a 
light feed. In this manner glass can be drilled with small 
holes, up to 3-16 inch in diameter nearly as rapidly as cast 
steel. 

Cement for Pipe Joints. Mix 10 parts iron filings and 3 
parts chloride of lime to a paste by means of water. Apply 
to the joint and clamp up. It will be solid in 12 hours. 

Hardening Tools. For heavy planer or lathe tools, when 
steel has been selected at random and is found a little too 
low in hardening properties for the purpose, to one pail 
of soft water, add % pound of cyanide potassium, 1 pound 
of salt, 1 dessert spoonful of oil of vitriol. Draw the tem- 
per slightly. 

Paint for Iron. Dissolve y 2 pound of asphaltum and y 2 
pound of pounded resin in 2 pounds of tar oil. Mix hot in 
an iron kettle, but do not allow it to come in contact with 
the fire. It may be used as soon as cold, and is good both 
for outdoor wood and ironwork. 



SHOP KINKS 563 

Stamping Names on Tools. No name stamp or steel let- 
ters and figures can be made that will stand to stamp saw 
blades or steel tools. They will stamp all soft metals, such 
as brass, copper, soft cast or wrought iron, or annealed 
cast steel. 

Never stamp a name on a steel rule, square or any fine 
tool as it will throw it out of true. To mark such tools 
use etching acid. 

How to Anneal Brass or Copper. In working brass and 
copper, it will become hard, and if hammered to any great 
extent will split. To prevent cracking or splitting, the 
piece must be heated to a dull red heat and plunged into 
cold water; this will soften it so it can be worked easily. 
Be careful not to heat brass too hot, or it will fall to 
pieces. The piece must be annealed frequently during the 
process of hammering. 

The Relative Weight of Different Metals. The weight of 
wrought iron being 1, cast iron will be 0.95, steel 1.02, cop- 
per 1.16, brass 1.09 and lead 1.48. 

To Find the Diameter of a Driving Pulley. Multiply the 
diameter of the driven by the number of its revolutions 
and divide the product by the number of revolutions of 
the driver. The quotient will be the diameter of the driver. 

To Find the Diameter of a Driven Pulley. Multiply the 
diameter of the driver by the number of its revolutions 
and divide the product by the number of revolutions of the 
driven. The quotient will be the diameter of the driven. 

To Find the Speed of a Driven Pulley. Multiply the 
diameter of the driver by the number of its revolutions 
and divide by the diameter of driven. The quotient will 
be the number of revolutions of the driven. 

Protecting Bright Work from Rust. Use a mixture of 
one pound of lard, one ounce of gum camphor, melted to- 
gether, with a little lamp-black. A mixture of lard oil 
and kerosene in equal parts. A mixture of tallow and 
white lead, or of tallow and lime. 



564 MACHINE SHOP PRACTICE 

Removing Scale from Iron Castings. Immerse the parts 
in a mixture composed of one part of oil of vitriol to three 
parts of water. In six to ten hours remove the eastings, 
and wash them thoroughly with clean water. A weaker 
solution can be used by allowing a longer time for the 
action of the solution. 

How to Braze. Clean the article thoroughly, and better 
to polish with sand paper. Fasten the parts to be brazed 
firmly together, so they will not part when heated in the 
fire. Place over a slow fire of charcoal or well coked coal. 
Place on the parts to be brazed a small quantity of pul- 
verized borax; as soon as this is done boiling and has 
flowed to all parts, then put on the spelter; when the 
spelter melts it will generally run in globules or shot. Jar 
the piece by gently striking with a small piece of wire; 
this will cause the spelter to flow to all parts. 

Lead Explosions. Many mechanics have had their 
patience sorely tried when pouring lead around a damp or 
wet joint, to have it explode, blow out or scatter from the 
effects of steam generated by the heat of the lead. The 
whole trouble may be avoided by putting a piece of resin, 
the size of a man's thumb, into the ladle and allowing it to 
melt before pouring. 

Metal that Expands in Cooling. A metal that will ex- 
pand in cooling is made of 9 parts lead, 2 parts antimony 
and 1 part bismuth. This metal is valuable for filling 
holes in castings. 

Fastening Leather to Iron. A good way to glue leather to 
iron is to paint the iron with a mixture of white lead 
and lamp black dissolved in oil. Then cover with a cement 
made of the best glue soaked in water until soft, and then 
dissolved in vinegar. This is thoroughly mixed with one- 
third of its bulk of white pine turpentine, and thinned 
with vinegar until it can be spread with a brush. It 
should be applied to the iron while it is hot and the leather 



SHOP KINKS 565 

put on and quickly pressed into place. It must be held 
tight by a clamp while drying. 

Cleaning Chased Brass. Chased brass of any kind, may 
be cleaned as follows: Wash well with hot water and soap 
and dry thoroughly, then rub all over with a lemon cut in 
half. When it looks quite clean, rinse well in warm water, 
dry and polish with a chamois leather. Chased work of 
any kind should not be cleaned with powder. 

Cleaning Brass Castings. If greasy, the castings should 
be cleaned by boiling in lye or potash. The first pickle is 
composed of nitric acid one quart, water six to eight quarts. 
After pickling in this mixture the castings should be 
washed in clear warm or hot water, and the following 
pickle be then used: Sulphuric acid one quart, nitric acid 
two quarts, muriatic acid, a few drops. The first pickle 
will remove the discolorations due to iron, if present. The 
muriatic acid of the second pickle will darken the color 
of the castings to an extent depending on the amount used. 

Preventing Rust on Machinery. A good mixture for use 
as a slush to prevent the rusting of machinery is made by 
dissolving 1 ounce of camphor in 1 pound of melted lard, 
skim off the impurities and add enough black lead to give 
the mixture an iron color. After cleaning the machinery 
carefully, smear on the mixture. It can be left indefinitely, 
or if wiped off after 24 hours will prevent rust for some 
time. When removed, the metal should be polished with a 
soft cloth. 

Hard Cement. Hard cement is made with 16 ounces of 
fine cast iron turnings and 1 ounce of Sal-Ammoniac, wet 
with water to the consistency required. 

Leaky Boiler Flues. Boilers frequently leak along a seam 
or about a flue. This can generally be stopped by putting 
a pint of corn meal in the boiler. 

Laying out Work. In laying out work on planed surfaces 
of steel or iron, use blue vitriol and water on the surface. 
This will copper-plate the surface nicely, so that all lines 



566 MACHINE SHOP PRACTICE 

will show plainly. If on oily surfaces, add a little oil of 
vitriol, this will eat the oil off and leave a nicely coppered 
surface. 

Eemoving Stains. To remove Ink Stains, wash with pure 
fresh water, and apply oxalic acid. If this changes the 
stain to a red color, apply ammonia. To remove Iron Rust 
from White Fabrics, saturate the spots with lemon juice 
and salt and expose to the sun. 

Weight of Castings. If you have a pattern made of soft 
pine, put together without nails, an iron casting made from 
it will weigh sixteen pounds to every pound of the pattern. 
If the casting is of brass, it will weigh eighteen pounds to 
every pound of the pattern. 

Ordering Taps and Dies. In ordering Taps and Dies, be 
sure and give the kind, exact size and thread wanted. Al- 
ways remember you are writing to a person who knows 
nothing of what is wanted, therefore make the order plain 
and explicit. Never order a special Tap or Die if it can 
be avoided, as such will cost at least double that of regu- 
lar sizes and threads. 

Tapping Nuts. Always use good Lard Oil in cutting 
threads with a die or tapping out nuts. Poor cheap oil 
will soon ruin both die and tap. 

Grindstones. Grindstones to grind machinists' tools 
should be run at a speed of about 800 feet per minute at 
its periphery, a 30-inch stone should be run about 100 rev- 
olutions per minute. When used to grind carpenters' tools 
a speed of 600 feet at its periphery, a 30-inch stone should 
therefore be run at 75 revolutions per minute. 

White Metal for Bearings. White metal for bearings 
consists of 48 pounds of tin, 4 pounds of copper, and 1 
pound of antimony. The copper and tin are melted first, 
and then the antimony is added. 

Marine Glue. One part of pure india rubber dissolved 
"in naphtha. When melted add two parts of shellac. Mel* 



SHOP KINKS 567 

until mixed. Pour out on tin until cold. Melt and use 
with a brush at water-bath heat. 

Or take a handful of quicklime and four ounces of lin- 
seed oil. Boil, and pour out on a plate until hard. Melt 
and use. 

Or take one pound of common glue— not fish glue— in 
two quarts of skim milk. Soak and boil. 

Tempering Chisels. To 3 gallons water add 3 ounces 
spirits nitre, 3 ounces white vitriol, 3 ounces sal ammo- 
niac, 3 ounces alum, 6 ounces salt with a double handful 
of hoof parings. Heat the tool to a cherry red. This has 
put new life in steel that has apparently been burned, and 
is used to temper chisels for cutting mill stones. 

Soldering Fluid. Take of scrap zinc or pure spelter 
about ^4 pound, and immerse in a half-pint of muriatic 
acid. If the scraps completely dissolve add more until 
the acid ceases to bubble and a small piece of metal re- 
mains. Let this stand for a day and then carefully pour 
off the clear liquid, or filter it through a cone of blotting 
paper. Add a teaspoonful of sal-ammoniac, and when 
thoroughl}' dissolved, the solution is ready for use. De- 
pending on the materials to be soldered, the quantity of 
sal-ammoniac can be reduced. Its presence makes solder- 
ing very easy, but, unless the parts are well heated so as 
to evaporate the salt, the joints may rust. 

Soldering Aluminium. When soldering aluminium, it 
should be borne in mind that upon exposure to the air a 
slight film of oxide forms over the surface of the alumin- 
ium, and afterwards protects the metal. The oxide is the 
same color as the metal, so that it cannot easily be distin- 
guished. The idea in soldering is to get underneath this 
oxide while the surface is covered with the molten solder. 
Clean off all dirt and grease from the surface of the metal 
with a little benzine, apply the solder with a copper bit, 
and when the molten solder is covering the surface of the 
metal, scratch through the solder with a steel wire scratch- 



568 MACHINE SHOP PRACTICE 

brush. By this means the oxide on the surface of the 
metal is broken up underneath the solder, which contain- 
ing its own flux, takes up the oxide and enables the sur- 
face of the aluminium to be tinned properly. 

Preventing Iron or Steel from Rusting. The best treat- 
ment for polished iron or steel, which has a habit of 
growing gray and lustreless, is to wash it very clean with 
a stiff brush and ammonia soapsuds, rinse well and dry by 
heat if possible, then oil plentifully with sweet oil and dust 
thickly with powdered quick lime. Let the lime stay on 
two days, then brush it off: with a clean stiff brush. Pol- 
ish with a softer brush, and rub with cloths until the 
lustre comes out. By leaving the lime on, iron and steel 
may be kept from rust almost indefinitely. 

Lubricant for Milling. Dissolve separately in water, 10 
pounds of soap and 15 pounds of sal-soda. Mix this in 
40 gallons of clean water. Add two gallons of best lard 
oil, stir thoroughly, and the solution is ready for use. 

Lubricant for Drilling. Dissolve three-fourths to one 
pound of sal-soda in one pailful of water. 

Clamping Work to a Face Plate. In doing many kinds 
of work it is necessary to bolt or clamp a piece to the 
face plate, and many times it is very difficult to keep the 
piece from slipping, especially if it becomes necessary to 
take a heavy chip in turning or boring. If you will put 
a piece of thin paper between the article and face plate, 
you will find no difficulty in holding it to its place. 

Speed of Emery Wheels. Never run an emery wheel 
without positively knowing how many revolutions the arbor 
is making in a minute. Never guess at the speed. The 
only sure way to find this out is to use a good speed indi- 
cator and time it carefully with your watch. 

Lubricating Oil. Never buy poor oil to use on shafting 
or machinery of any kind. It will soon gum up the bear- 
ings and take double the power to run the factory, be- 
sides it will wear out your machinery and patience. Good 



SHOP KINKS 569 

oil is by far the cheapest. Among the best oils for sew- 
ing machines or other light machinery is sperm (whale) 
oil to which add one-tenth part kerosene oil. 

Horse Power of Belting. One hundred square feet of 
belting running over a pulley per minute, will give one 
horse power; example— a 2-inch belt running over a pulley 
24 inches in diameter, running 100 revolutions per min- 
ute, will practically transmit one horse power 

Making Pipe Joints. Never screw pipe together for 
either steam, water or gas without putting white or red 
lead on the joints. 

Many times in taking pipe apart the joints are stuck so 
hard that it is impossible to unscrew the pipe; heat the 
coupling (not the pipe) by holding a hot iron on it, or ham- 
mer the coupling Avith a light hammer, either one will ex- 
pand the coupling and break the joint so it can be easily 
unscrewed. 

Cored or Rough Holes, ^ever use a Tap m a cored or 
rough hole. Always run a heavy flat drill through the 
hole to take out the scale, sand, or projections. 

Cutting Threads with a Die. Always use good lard oil 
in cutting threads with a die. Many times a die is ruined 
the first time it is used, because there is no oil put on the 
work. Use plenty of oil. 

Improper Use of Taps. Never use a tap in any metal, 
especially cast iron, without using plenty of good oil. 
Many taps are ruined the first time they are used by lack 
of oil. The tap will gauld in any metal and tear the 
threads off unless well oiled. 

Turning or Drilling Solutions. Strong sal soda water 
or soapy water is much better than clean water to use 
where water cuts are being taken, either on lathe or 
planer. 

Proper Way to Use a Monkey Wrench. Never pull a 
monkey wrench backwards or from the jaws. Always pull 



570 MACHINE SHOP PRACTICE 

towards the jaws, otherwise the bar of any wrench made 
may be bent in this manner. 

Improper Use of Reamers. Never use a reamer to ream 
out pipe of any kind. The scale inside of pipe caused by 
the flux used in welding or brazing is as hard as glass, 
and no reamer can be made hard enough to cut it. 

Getting Rid of Vermin. Insects may be destroyed by 
putting alum in water and letting it boil until it is all 
dissolved; apply hot with a brush and all creeping things 
are instantly destroyed without any danger to human life 
or injury to property. 

Hardening Lathe Centers. The point of center should 
be heated to a bright red, then cooled in clean, cold water. 
After it becomes cold; it should be withdrawn and the dirt 
cleaned at once from same, that color may be seen. Our 
centers should be drawn to a light straw color, on ac- 
count of the special grade of steel used. Care should be 
taken not to heat center very far back, as it is liable to be- 
come sprung should such be done. 

Gears for Screw Cutting. Take from the index the num- 
ber of threads cut by equal gears and multiply it by a 
number that will give for a product a gear on the index. 
Place this gear on the spindle or stud. Then multiply the 
number of threads per inch to be cut by the same number, 
and put the resulting gear on the screw. 

Example: Lathe cuts four threads by equal gears, and 
thirteen threads per inch are wanted, then 

Spindle or stud _ _4_ 
Threads to be cut 13 

The constant five will give for a product a gear on the 
. , 4X5 20 
mdeX I^ = 65 

Therefore, to cut thirteen threads per inch, would require 
a gear of twenty teeth on the spindle or stud, and a gear 
of sixty-five teeth on the lead screw. 



SHOP KINKS 571 

Cutting Speeds. Assuming 36 feet as the proper cutting 

speed in feet per minute for cast iron, which equals about 

140 revolutions per minute for one inch in diameter to be 

turned, divide the number 140 by the outside diameter of 

the work, which gives the proper number of revolutions. 

140 
Example: Diameter of work is 5 inches, then •— = 28 

5 

revolutions. 

The following table gives the constants for different cut- 
ting speeds: 



Cutting Speed 
in Feet. Constant 




36 




140 


Cast iron. 


31 




120 


Malleable iron. 


26 




100 


Steel. 


21 




80 


Steel. 


16 




60 


Steel. 


13 




50 


Hardened steel and chilled cast iron 



Removing Rust from Iron. Iron may be quickly and 
easily cleaned by dipping in or washing with nitric acid 
one part, muriatic acid one part and water twelve parts. 
After using wash with clean water. 

Cement for Fastening Paper or Leather to Iron. One 
pound of the best flour, *4 pound of the best glue, V2 
pound of granulated sugar, y 2 ounce of powdered borax, 
y% ounce of sal-ammoniac, ^4 ounce of alum. Soak the 
glue in three pints of water for 12 hours. Mix the flour 
in one quart of water, mix all together, and boil over a 
slow fire, or cook with a steam jet. When cool it is ready 
for use. The face of the pulley or surface where the 
leather is to be applied must be thoroughly clean and free 
from grease. 

Scratch Awl for Fine Work. A common sewing needle 
held in a suitable handle makes an excellent scriber for 
accurate work. It is so cheap that grinding is unneces- 



572 MACHINE SHOP PRACTICE 

sary, when dull, it can be replaced by a new one. The 
point on a needle is ground by an expert, and is far su- 
perior to anything possible to be made by the ordinary 
machinist. 

Testing Glue. Break a cake of the glue into several 
pieces, either by striking it a blow with a hammer or by 
bending it. If the broken pieces have smooth, even edges, 
the glue is of poor quality. If the edges are very ragged, 
the quality is good. The more splinters at the broken edges 
the more the glue is to be depended upon and will stand 
damp weather well. 

Loosening Rusted Screws. One of the simplest and readi- 
est ways of loosening a rusted screw is to apply heat to the 
head of the screw. A small bar or rod of iron, flat at the 
end, if reddened in the fire and applied for two or three 
minutes to the head of a rusty screw, will, as soon as it 
heats the screw, render its withdrawal as easy with the 
screwdriver as if it were only a recently inserted screw. 
This is not particularly novel, but it is worth knowing. 

Ordering Drill Rods. In ordering drill rods, or number 
twist drills, be very careful and give the right number 
wanted, also state what gauge and the maker's name of 
the gauge ordered from. There are hardly two gauges 
made that are of the same size. It is better to order by 
l,000ths. 

How to Soften Files. To soften small files cover them 
with oil and hold them over a fire until the oil blazes. As 
soon as the flame runs all over the file, plunge it into 
water. 

Recipe for Heat-Proof Paint. A good cylinder and ex- 
haust pipe paint is made as follows: 

Two pounds of black oxide of manganese, 3 pounds of 
graphite and 9 pounds of Fuller's earth, thoroughly mixed. 
Add a compound of 10 parts of sodium silicate, 1 part of 
glucose and 4 parts of water, until the consistency is such 
that it can be applied with a brush. 



SHOP KINKS 573 

To Soften Cast Iron. Heat the whole piece to a bright 
glow and gradually cool under a covering of fine coal dust. 
Small objects should be packed in quantities, in a crucible 
in a furnace or open fire, under materials which when 
heated to a glow give out carbon to the iron. They should 
be heated gradually, and kept at a bright heat for an hour 
and allowed to cool slowly. The substances recommended 
to be added are cast-iron turnings, sodium carbonate or 
raw sugar. If only raw sugar is used, the quantity should 
not be too small. By this process it is said that cast iron 
may be made so soft that it can almost be cut with a 
pocket-knife. 

To Harden Files. To harden files dip the file in red- 
hot lead, handle up. This gives a uniform heat and pre- 
vents warping. Run the file endwise back and forth in a 
pan of salt water. Set the file in a vise and straighten 
it while still warm. 

Leather Belts. A leather belt is more economical in the 
end than a rubber one. When buying a leather belt it 
should be tested by doubling it up with the hair side out. 
If it should crack, reject it as it cannot realize the whole 
amount of power it should transmit. If it shows a spongy 
appearance it should be condemned at once, for it must be 
pliable as well as firm. The grain or hair side should be 
free from wrinkles and the belt should be of uniform 
thickness throughout its length. It should be tested for 
quality by immersing a small strip in strong vinegar. If 
the leather has been properly tanned and is of good qual- 
ity, it will remain in vinegar for weeks without alteration, 
excepting it will grow darker in color. If the leather has 
not been properly tanned the fiber will swell and the 
leather will become softened, turning it into a jelly-like 
mass. 

To Cement Rubber to Leather. Roughen both surfaces 
with a sharp piece of glass, apply on both a diluted solu- 
tion of gutta percha in carbon bisulphide, and let the so- 



574 MACHINE SHOP PRACTICE 

lution soak into the material. Then press upon each sur- 
face a skin of gutta percha about one-hundredth of an 
inch in thickness, between a pair of rolls. Unite the two 
surfaces in a press that should be warm but not hot. In 
case a press cannot be used, dissolve 30 parts of rubber 
in 140 parts of carbon bisulphide, the vessel being placed 
on a water bath of a temperature of 86 degrees Fahren- 
heit. Melt ten parts of rubber with fifteen parts of rosin 
and add 35 parts of oil of turpentine. When the rubber 
has been completely dissolved, the two liquids may be 
mixed. The resulting cement must be kept well corked. 

Drilling Holes in Glass. Holes of any size desir*ed may 
be drilled in glass by the following method: Get a small 
3-cornered file and grind the points from one corner and 
the bias from the other and set the file in a brace, such as 
is used in boring wood. Lay the glass in which the holes 
are to be bored on a smooth surface covered with a blanket 
and begin to bore a hole. When a slight impression is 
made on the glass, place a disk of putty around it and fill 
with turpentine to prevent too great heating by friction. 
Continue boring the hole, which will be as smooth as one 
drilled in wood with an auger. Do not press too hard on 
the brace while drilling. 

To Polish Brass. Smooth the brass with a fine file and 
rub it with a smooth fine grain stone, or with charcoal and 
water. When quite smooth and free from scratches, polish 
with pumice stone and oil, spirits of turpentine, or alcohol. 

How to Make a Soft Alloy. A soft alloy which will 
adhere tenaciously to metal, glass or porcelain, and can 
also be used as a solder for articles which cannot bear a 
high degree of heat, is made as follows: 

Obtain copper-dust by precipitating copper from the 
sulphate by means of metallic zinc. Place from 20 to 36 
parts of the copper-dust, according to the hardness de- 
sired, in a porcelain-lined mortar, and mix well with some 
sulphuric acid of a specific gravity of 1.85. Add to this 



SHOP KINKS 575 

paste 70 parts of mercury, stirring constantly, and when 
thoroughly mixed, rinse the amalgam in warm water to 
remove the acid. Let cool from 10 to 12 hours, after 
which time it will be hard enough to scratch tin. 

When ready to use it, heat to 707 degrees Fahrenheit 
and knead in an iron mortar till plastic. It can then be 
spread on any surface, and when it has cooled and hard- 
ened will adhere most tenaciously. 



Things to Do in Case of Sprains or Dislocations. The 

most important thing is to secure rest iftitil the arrival of 
the surgeon. If the sprain is in the ankle or foot, place 
a folded towel around the part and cover with a bandage. 
Apply moist heat. The foot should be immersed in a 
bucket of hot water and more hot water added from time 
to time, so that it can be kept as hot as can be borne for 
fifteen or twenty minutes, after which a firm bandage 
should be applied, by a surgeon, if possible, and the foot 
elevated. 

In sprains of the wrist, a straight piece of wood should 
be used as a splint, cover with cotton or wool to make it 
soft, and lightly bandage, and carry the arm in a sling. 
In all cases of sprains the results may be serious, and a 
surgeon should be obtained as soon as possible. After the 
acute symptoms of pain and swelling have subsided, it 
is still necessary that the joint should have complete rest 
by the use of a splint and bandage and such applications 
as the surgeon may direct. 

Simple dislocation of the fingers can be put in place by 
strong pulling, aided by a little pressure on the part of 
the bones nearest the joint. 

The best that can be done in most eases is to put the 
part in the position easiest to the sufferer, and to apply 
cold wet cloths, while awaiting the arrival of a surgeon. 

To Remove Foreign Substances from the Eye. Take hold 
of the upper lid and turn it up so that the inside of the 
upper lid may be seen. Have the patient make several 
movements with the eye, first up, then down, to the right 
side and to the left. Then take a tooth-pick with a little 
piece of absorbent cotton wound around the end and mois- 
tened in cold water, and swab it out. The foreign sub- 

579 



580 MACHINE SHOP PRACTICE 

stance will adhere to the swab and the object will be re- 
moved from the eye without any trouble. 

In Case of Cuts. The chief points to be attended to are: 
Arrest the bleeding-. Remove from the wound all foreign 
substances as soon as possible. Bring the wounded parts' 
opposite to each other and keep them so. This is best done 
by means of strips of surgeon's plaster, first applied to 
one side of the wound and then secured to the other. 
These strips should not be too broad, and space must be 
left between the strips to allow any matter to escape. 
Wounds too extensive to be held together by plaster must 
be stitched by a surgeon, who should always be sent for 
in severe cases. 

Broken Limbs. To get at a broken limb or rib, the 
clothing must be removed, and it is essential that this 
should be done without injury to the patient. The simplest 
plan is to rip up the seams of such garments as are in the 
way. Shoes must always be cut off. It is not imperatively 
necessary to do anything to a broken limb before the ar- 
rival of a doctor, except to keep it perfectly at rest. 

Wounds. If a wound be discovered in a part covered by 
the clothing, cut the clothing at the seams. Remove only 
sufficient clothing to uncover and inspect the wound. 

All wounds should be covered and dressed as quickly as 
possible. If a severe bleeding should occur, see that this 
is stopped, if possible, before the wound is dressed. 

Treatment of Burns. In treating burns of a serious na- 
ture, the first thing to be done after the fire is extin- 
guished should be to remove the clothing. The greatest 
care must be exercised, as anything like pulling will bring 
the skin away. If the clothing is not thoroughly wet, be 
sure to saturate it with water or oil before attempting to 
remove it. 

If portions of the clothing will not drop off, allow them 
to remain. Then make a thick solution of common baking 
soda and water, and dip soft cloths in it and lay them 



MEDICAL AID 581 

over the injured parts, and bandage them lightly to keep 
them in position. Have the solution near by, and the in- 
stant any part of a cloth shows signs of dryness, squeeze 
some of the solution on that part. Do not remove the 
cloth, as total exclusion of the air is necessary, and little, 
if any, pain will be felt as long as the cloths are kept sat- 
urated. This may be kept up for several days, after which 
soft cloths dipped in oil may be applied, and covered with 
cotton batting. If the feet are cold, apply heat and give 
hot water to drink, and if the burns are very serious send 
for a doctor as soon as possible. The presence of pain is 
a good sign, showing that vitality is present. 

Bleeding. In case of bleeding, the person may become 
weak and faint, unless the blood is flowing actively. This 
is not a serious sign, and the quiet condition of the faint 
often assists nature in stopping the bleeding, by allowing 
the blood to clot and so block up any wound in a blood 
vessel. 

Unless the faint is prolonged or the patient is losing 
much blood, it is better not to relieve the faint condition. 
When in this state excitement should be avoided, and ex- 
ternal warmth should be applied, the person covered with 
blankets, and bottles of hot water or hot bricks applied 
to the feet and arm-pits. 

Watch carefully if unconscious. 

If vomiting occurs, turn the patient's body on one side, 
with the head low, so that the matters vomited may not 
go into the lungs. 

Bleeding is of three kinds: From the arteries which lead 
from the heart. That which comes from the veins which 
take the blood back to the heart. That from the small 
veins which carry the blood to the surface of the body. 
~n the first, the blood is bright scarlet and escapes as 
though it were being pumped. In the second, the blood is 
lark red and flows away in an uninterrupted stream. In 



582 MACHINE SHOP PRACTICE 

the third, the blood oozes out. In some wounds all three 
kinds of bleeding occur at the same time. 

Carrying an Injured Person. In case of an injury where 
walking is impossible, and lying down is not absolutely 
necessary, the injured person may be seated in a chair, 
and carried, or he may sit upon a board, the ends of which 
are carried by two men, around whose necks they should 
place his arms so as to steady himself. 

Where an injured person can walk he will get much help 
by putting his arms over the shoulders and round the necks 
of two others. 



The Metric System. Although the Metric System was 
legalized by the United States Government in 1866, it has 
been little used in this country outside of the school room 
and laboratory. 

The recent great expansion of the foreign trade of the 
United States has, however, brought about conditions which 
render some knowledge of the Metric System and its equiv- 
alents in our ordinary standards of weights and measures 
very useful, if not absolutely necessary, both to the man- 
ufacturer and mechanic. 

The Metric System is based on the meter, which was 
designed to be one ten-millionth part of the earth's merid- 
ian, passing through Dunkirk and Formentera. Later in- 
vestigations, however, have shown that the meter exceeds 
one ten-millionth part by almost one part in 6400. The 
value of the meter, as authorized by the United States 
Government, is 39.37 inches. 

The three principal units are the meter, the unit of 
length. The liter, the unit of capacity, and the gram, the 
unit of weight. Multiples of these are obtained by pre- 
fixing the Greek words: Deka 10, hekto 100, and kilo 
1,000. Divisions are obtained by prefixing the Latin words: 
Deci 1-10, centi 1-100, and milli 1-1000. Abbreviations of 
the multiples begin with a capital letter, and of the divi- 
sions with a small letter, as, for example: Dekameter is 
abbreviated thus, Dm, and Decimeter thus, dm. 

The liter is equal to the volume occupied by 1 cubic 
decimeter. The gram is the weight of one cubic centimeter 
of pure distilled water at a temperature of 39.2 degrees 
Fahrenheit, the kilogram is the weight of 1 liter of water, 
the tonne is the weight of 1 cubic meter of water. 

585 



586 MACHINE SHOP PRACTICE 

The Metric System of Measurement. 



Table No. 23— Measures of Length. 

1 Millimeter (mm.) = 0.03937 inches, or about -%t inches 
10 Millimeters = 1 Centimeter (cm.) = 0.393 inches 
10 Centimeters = 1 Decimeter (dm.) = 3.937 inches 
10 Decimeters = 1 Meter (m.) = 39.370 inches, 3.280 feet, 

or 1.093 yards 
10 Meters = 1 Dekameter (Dm.) = 32.808 feet 
10 Dekameters = 1 Hektometer (Hm.) = 19.927 rods 
10 Hektometers = 1 Kilometer (Km.) = 1093.61 yards, or 

0.621 mile 
10 Kilometers = lMyriameter (Mm.) — 6.213 miles 
1 inch = 2.54 cm. 1 foot = 0.3048 m. 1 yard = 0.9144 m. 

1 rod = 0.502 Dm. 1 mile = 1.609 Km. 



Table No. 24 — Measures of Weight. 

1 Gramme (g.) = 15.432 grains Troy, or 0.032 ounce Troy, 
or 0.035 ounce avoirdupois 
10 Grammes = 1 Dekagramme (Dg.) = 0.352 oz. avoir. 
10 Dekagrammes = 1 Hektogramme (Hg.)= 3.527 oz. avoir. 
10 Hektogrammes = 1 Kilogramme (Kg.) = 2.204 pounds 
1000 Kilogrammes = 1 Tonne (T.) = 2204.621 pounds, or 
1.102 tons of 2000 pounds, or 0.984 tons of 2240 pounds 
1 grain — 0.064 g. 1 ounce avoirdupois = 28.35 g. 

1 ton 2000 pounds = 0.9072 T. 



Table No. 25 — Measures of Capacity. 

1 Liter (1.) = 1 cubic decimeter = 61.027 cubic inches, or 
0.035 cubic feet, or 1.056 liquid quarts, or 0.908 dry 
quarts, or 0.264 gallon. 
10 Liters = 1 Dekaliter (Dl.) = 2.641 gallons, or 1.135 pecks 
10 Dekaliters = 1 Hektoliter (HI.) = 2.8375 bushels 
10 Hektoliters = 1 Kiloliter (Kl, ) — 61027.05 cubic inches, 
or 28.375 bushels. 
1 cubic foot = 28.317 1. lgallon = 3.785 1. 



TABLES 



587 



Table No. 26— Decimal Equivalents 


of Millimeters 




and Fractions of Millimeters. 






1 mm. == : 


.03937 inches. 




Mm. 


Inches. 


Mm. 


Inches. 


Mm. 


Inches. 


1-50 


= .00079 


26-50 


= .02047 


2 


= .07874 


2-50 


.00157 


27-50 


.02126 


3 


.11811 


3-50 


,00236 


28-50 


.02205 


4 


.15748 


4-50 


.00315 


29-50 


.02283 


5 


.19685 


5-50 


.00394 


30-50 


.02362 


6 


.23622 


6-50 


.00472 


31-50 


.02441 


7 


.27559 


7-50 


.00551 


32-50 


.02520 


8 


.31496 


8-50 


.00630 


33-50 


.02598 


9 


.35433 


9-50 


.00709 


34-50 


.02677 


10 


.39370 


10-50 


.00787 


35-50 


.02756 


11 


.43307 


11-50 


.00866 


36-50 


.02835 


12 


.47244 


12-50 


.00945 


37-50 


.02913 


13 


.51181 


13-50 


.01024 


38-50 


.02992 


14 


.55118 


14-50 


.01102 


39-50 


.03071 


15 


.59055 


15-50 


.01181 


40-50 


.03150 


16 


.62992 


16-50 


.01260 


41-50 


.03228 


17 


.66929 


17-50 


.01339 


42-50 


.03307 


18 


.70866 


18-50 


.01417 


43-50 


.03386 


19 


.74803 


19-50 


.01496 


44-50 


.03465 


20 


.78740 


20-50 


.01575 


45-50 


.03543 


21 


.82677 


21-50 


.01654 


46-50 


.03622 


22 


.86614 


22-50 


.01732 


47-50 


.03701 


23 


.90551 


23-50 


.01811 


48-50 


.03780 


j 24 


.94488 


24-50 


.01890 


49-50 


.03858 


24 


.98425 


25-50 


.01969 


1 


.03937 


26 


1.02362 



10 Millimeters = 1 Centimeter = 0.3937 inches. 
10 Centimeters = 1 Decimeter = 3.937 inches. 
10 Decimeters = 1 Meter = 39.37 inches. 
2.54 Centimeters = 1 inch. 



588 



MACHINE SHOP PRACTICE 





Table No. 27 — Tapers and 


Angles. 




Taper 
Per Foot 


Whole Angle. 


Half Angle with 
Center Line. 


Taper Per 
Inch of 
Whole 
Angle. 


Taper Per 

Inch from 

Center 

Line or 

Half 

Angle. 


Deg. 


Min. 


Deg. 


Min. 


% 





36 





18 


.010416 


.005203 


3 





54 





27 


.015625 


.007812 


X 


1 


12 





36 


.020833 


.010416 


5 


1 


30 





45 


.026042 


.013021 


% 


1 


47 





53 


.031250 


.015625 


7 


2 


05 


1 


02 


.036458 


.018229 


X A 


2 


23 


1 


11 


.041667 


.020833 


A 


2 


42 


1 


21 


.046875 


.023438 


% 


3 


00 


1 


30 


.052084 


.026042 


Tfr 


3 


18 


1 


39 


.057292 


.028646 


% 


3 


25 


1 


47 


.062500 


.031250 


1 3 


3 


52 


1 


56 


.067708 


.033854 


% 


4 


12 


2 


06 


.072917 


.036456 


1 5 


4 


28 


2 


14 


.078125 


.039063 


1 


4 


45 


2 


23 


.083330 


.041667 


IX 


5 


58 


2 


59 


.104666 


.052084 


IX 


7 


08 


3 


34 


.125000 


.062500 


1% 


8 


20 


4 


10 


.145833 


.072917 


2 


9 


32 


4 


46 


.166666 


.083332 


2X 


11 


54 


5 


57 


.208333 


.104166 


3 


14 


16 


7 


08 


.250000 


.125000 


3% 


16 


36 


8 


18 


.291666 


.145833 


4 


18 


54 


9 


27 


.333333 


.166666 


4% 


21 


40 


10 


50 


.375000 


.187500 


5 


24 


04 


12 


02 


.416666 


.208333 


6 


28 


06 


14 


03 


.500000 


.250000 






TABLES 



589 



Table No. 


28 — Machine or Nut Taps. 


Diameter. 


Length in 
Inches. 


Threads Per Inch. 


Standard 
Size. 


Rough Iron 
Size. 


U. S. 
Standard. 


V 
Standard. 


Whitworth 
Standard. 


X A 


1 7 

Si 


5 


20 


20 


20 




9 


5 


20 


20 




A 


21 


5% 


18 


18 


18 




1 1 
3T 


5X 


18 


18 




% 


25 


6 


16 


16 


16 




1 3 


6 


16 


16 




7 


29 
-6T 


6% 


14 


14 


14 




1 5 
T2" 


6% 


14 


14 




X 


33 


7 


13 


12 


12 




1 7 


7 


13 


12 




A 


37 


7% 


12 


12 


12 




1 9 


7X 


12 


12 




% 


41 
~6T 


8 


11 


11 


11 




21 


8 


11 


11 




tt 


23 
3F 


8% 


11 


11 


11 


% 


25 
T2" 


9 


10 


10 


10 


1 3 
T"6" 


27 


9% 


10 


10 


10 


% 


29 
ST 


10 


9 


9 


9 


1 5 


31 


10X 


9 


9 


9 


1 


l^V 


11 


8 


8 


8 


1A 




11 


8 


8 





590 



MACHINE SHOP PRACTICE 






Table No. 29- 


—Hob or Master Taps. 






Number of Threads Per Inch. 


Diameter.. 


Length in 
Inches. 




U. S. 
Standard. 


V Standard. 


Whitworth 
Standard. 


X 


2% 


20 


20 


20 


5 


3X 


18 


18 


18 


% 


3X 


16 


16 


16 


1 


3X 


14 


14 


14 


X 


4 


13 


12 


12 


9 
1 6 


4X 


12 


12 


12 


% 


4X 


11 


11 


11 


1 1 


4% 


11 


11 


11 


3/ 


5 


10 


10 


10 


1 3 
T"6" 


5X 


10 


10 


10 


% 


5X 


9 


9 


9 


1 5 
T~6~ 


5X 


9 


9 


9 




6 


8 


8 


8 


1% 


6X 


7 


7 


7 


IX 


6% 


7 


7 


7 


1% 


7 


6 


6 


6 


IX 


7X 


6 


6 


6 


1% 


8 


5X 


5 


5 


1% 


8X 


5 


5 


5 


1% 


9 


5 


4X 


4X 


2 


9X 


4X 


4X 


4X 



TABLES 



591 



Table No. 30 — Decimal Parts 


of an Inch. 


1-64 


.01563 


11-32 


.34375 


43-64 


.67188 


1-32 


.03125 


23-64 


.35938 


11-16 


.6875 


3-64 


.04688 


3-8 


.375 






1-16 


.0625 


■ 




45-64 


.70313 






25-64 


.39063 


23-32 


.71875 


5-64 


.07813 


13-32 


.40625 


47-64 


.73438 


3-32 


.09375 


27-64 


.42188 


3-4 


.75 


7-64 


.10938 


7-16 


.4375 






1-8 


.125 






49-64 


.76563 






29-64 


.45313 


25-32 


.78125 


9-64 


.14063 


15-32 


.46875 


51-64 


.79688 


5-32 


.15625 


31-64 


.48438 


13-16 


.8125 


11-64 


.17188 


1-2 


.5 






3-16 


.1875 






53-64 


.82813 






33-64 


.51563 


27-32 


.84375 


13-64 


.20313 


17-32 


.53125 


55-64 


.85938 


7-32 


.21875 


35-64 


.54688 


7-8 


.875 


15-64 


.23438 


9-16 


.5625 






1-4 


.25 






57-64 


89063 






37-64 


.57813 


29-31 


.90625 


17-64 


.26563 


19-32 


.59375 


59-64 


.92188 


9-32 


.28125 


39-64 


.60938 


15-16 


.9375 


19-64 


.29688 


5-8 


.625 






5-16 


.3125 






61-64 


.95313 






41-64 


.64063 


31-32 


.96875 


21-64 


.32813 


21-32 


.65625 


63-64 


.97438 



Table No. 


. 31 — Melting- Points of Alloys of Tin, 




Lead and Bismuth. 


Tin. 


Lead. 


Bismuth. 


Melting 
Point in 
Degrees 
Fahren- 
heit. 


Tin. 


Lead. 


Bismuth. 


Melting 
Point in 
Degrees 
Fahren- 
heit, 


2 


3 


5 


199 


4 


1 




372 


1 


1 


4 


201 


5 


1 




381 


3 


2 


5 


212 


2 


1 




385 


4 


1 


5 


246 


3 




1 


392 


1 




1 


286 


1 


1 




466 


2 




1 


334 


1 


3 




552 


3 


1 




367 











592 



MACHINE SHOP PRACTICE 



Speed of Twist Drills. 

This table has beem compiled from memoranda furnished 
by some of the best known manufacturers in the country. 
These speeds should not be exceeded under ordinary circum- 
stances. A feed of one inch in from 95 to 125 revolutions is 
all that should be required according to the size of the drill. 
At these speeds it will be necessary to used plenty of oil, or a 
solution of oil, potash and water, when drilling steel, wrought 
or cast iron. 

The table is based on a speed of periphery of the drill of 30 
feet per minute for steel, 35 feet per minute for cast iron and 
60 feet per minute for brass. It will be found advisable to 
vary the speeds given in the table somewhat, according as the 
material to be drilled is more or less refractory. 



Table No. 32— Speed of Twist Drills. 




Speed 


Speed 






Speed 


Speed 




Diameter 


for 


for 


Speed for 


Diameter 


for 


for 


Speed for 


of Drill. 


Soft 


Cast 


Brass. 


of Drill. 


Soft 


Cast 


Brass. 




Steel. 


Iron. 






Steel. 


Iron. 




l 


1824 


2128 


3648 


ItV 


108 


125 


215 


X 


912 


1064 


1824 


1% 


102 


118 


203 


3 


608 


710 


1216 


1A 


96 


112 


192 


456 


532 


912 


lX 


91 


106 


182 


5 
"T6" 


365 


425 


730 


ItV 


87 


101 


174 


% 


304 


355 


608 


1% 


83 


97 


165 


-h 


260 


304 


520 


ItV 


80 


93 


159 


% 


228 


266 


456 


IX 


76 


89 


152 


P 


203 


236 


405 


1 9 

Ik 


73 


85 


145 


182 


213 


365 


70 


82 


140 


H 


166 


194 


332 


m 


68 


79 


135 


% 


152 


177 


304 


\% 


65 


76 


130 


1 3 
T~5" 


140 


164 


280 


HI 


63 


73 


125 


Vs 


130 


152 


260 


IX 


60 


71 


122 


1 5 
T"ff 


122 


142 


243 


115 
J-TT 


59 


69 


118 


1 


114 


133 


228 


2 


57 


67 


114 



TABLES 



593 



29 Degree Screw Thread. 

Acme Standard. The various parts of the 29 Degree Screw 
Thread, Acme Standard, are obtained as follows: 

Width of Point of Tool for 

.3707 



Screw or Tap Thread 



Width of Screw or Nut Thd. = 



No. of Thds. per in 
.3707 



— . + 0052 



No. of Thds. per in. 
Diameter of Tap = Diameter of Screw -f .020 
Diameter of Tap or Screw at Root = 

Diameter of Screw — 
Depth of Thread = ( 



\No. of Linear Thds. per in. 

1 



+.020 



2 X No. of Thds. per in 



- + .010) 





Table 


No. 33— 


Thread 


Parts. 




Number of 
Threads per 
Linear Inch. 


Depth of 
Thread. 


Width at 
Top of 
Thread. 


Width at 

Bottom of 

Thread. 


Space at 
Top of 
Thread. 


Thickness at 
Root of 
Thread. 


1 


.5100 


.3707 


.3655 


.6293 


.6345 


1% 


.3850 


.2780 


.2728 


.4720 


.4772 


2 


.2600 


.1853 


.1801 


.3147 


.3199 


3 


.1767 


.1235 


.1183 


.2098 


.2150 


4 


.1350 


.0927 


.0875 


.1573 


.1625 


5 


.1100 


.0741 


.0689 


.1259 


.1311 


6 


.0933 


.0618 


.0566 


.1049 


.1101 


7 


.0814 


.0529 


.0478 


.0899 


.0951 


8 


.0725 


.0463 


.0411 


.0787 


.0829 


9 


.0655 


.0413 


.0361 


.0699 


.0751 


10 


.0600 


.0371 


.0319 


.0629 


.0681 



594 



MACHINE SHOP PRACTICE 



Table No. 34- 


-Double Depth op V and U. S. 




Standard Threads, 




Threads 
per in. 


u. s. 

Standard 
Double 
Depth. 


V Thread 
Double 
Depth. 


Threads 
per in. 


u. s. 

Standard 
Double 
Depth, 


V Thread 
Double 
Depth. 


64 


.02029 


.02706 


16 


.08118 


.10825 


60 


.02165 


.02887 


14 


.09278 


.12357 


56 


.02319 


.03093 


13 


.09992 


.13323 


50 


.02598 


.03464 


12 


.10825 


.14433 


48 


.02706 


.03608 


11 


.11809 


.15745 


44 


.02952 


.03936 


10 


.12990 


.17320 


40 


.03247 


.04330 


9 


.14433 


.19244 


36 


.03608 


.04811 


8 


.16237 


.21650 


32 


.04059 


.05412 


7 


.18555 


.24742 


30 


.04330 


.05773 


6 


.21650 


.28866 


28 


.04639 


.06185 


51 


.23618 


.31490 


26 


.04996 


.06661 


5 


' .25980 


.34650 


24 


.05412 


.07216 


4£ 


.28866 


.38488 


22 


.05904 


.07872 


4 


.32475 


.43300 


20 


.06495 


.08660 


H 


.37114 


.49435 


18 


.07216 


.09622 


3 


.43333 


.57733 



C = Double Depth of Thread. 

D — Outside Diameter. 

d sp Diameter at Bottom of Thread. 

Example: Find actual diameter at bottom of V thread, % 
inch diameter, 10 threads to the inch. In the V thread 
column opposite the 10 threads per inch, find the decimal 
.173 inches, this subtracted from the outside diameter of the 
thread is the diameter at bottom of thread, thus: 



D C d 

% inch . (.750 in. — .173 in.) = .577 in. 



TABLES 



595 



Table No. 35 — Diameter 


in Decimals 


of an Inch 


of Number Twist Drills 


and 


Steel Wire Gauge. 


No. 

1 


Diameter 
of Drill in 
Inches. 


No. 


Diameter 

of Drill in 

Inches. 


No. 


Diameter 

of Drill in 

Inches. 


No. 

61 


Diameter 

of Drill in 

Inches. 


.2280 


21 


.1590 


41 


.0960 


.0390 


2 


.2210 


22 


.1570 


42 


.0935 


62 


.0380 


3 


.2130 


23 


.1540 


43 


.0890 


63 


.0370 


4 


.2090 


24 


.1520 


44 


.0860 


64 


.0360 


5 


.2055 


25 


.1495 


45 


.0820 


65 


.0350 


6 


.2040 


26 


.1470 


46 


.0810 


66 


.0330 


7 


.2010 


27 


.1440 


47 


.0785 


67 


.0320 


8 


.1990 


28 


.1405 


48 


.0760 


68 


.0310 


9 


.1960 


29 


.1360 


49 


.0730 


69 


.02925 


10 


.1935 


30 


.1285 


50 


.0700 


70 


.0280 


11 


.1910 


31 


.1200 


51 


.0670 


71 


.0260 


12 


.1890 


32 


.1160 


52 


.0635 


72 


.0250 


13 


.1850 


33 


.1130 


53 


.0595 


73 


.0240 


14 


.1820 


34 


.1110 


54 


.0550 


74 


.0225 


15 


.1800 


35 


.1100 


55 


.0520 


75 


.0210 


16 


.1770 


36 


.1065 


56 


.0465 


76 


.0200 


17 


.1730 


37 


.1040 


57 


.0430 


77 


.0180 


18 


.1695 


38 


.1015 


58 


.0420 


78 


.0160 


19 


.1660 


39 


.0995 


59 


.0410 


79 


.0145 


20 


.1610 


40 


.0980 


60 


.0400 


80 


.0135 



596 



MACHINE SHOP PRACTICE 



Table No. 36— Dimensions of Wrought-Iron 
Pipe. 



Nominal 

Inside 
Diameter. 


Actual 

Outside 

Diameter in 

Inches. 


Actual 

Inside 

Diameter in 

Inches. 


Thickness 

of Metal in 

Inches. 


Threads 
per Inch. 


Length of 
Full Thread 
in Inches. 


X 


.405 


.270 


.068 


27 


.19 


X 


.540 


.364 


.085 ' 


18 


.29 


% 


.675 


.493 


.091 


18 


.30 


X 


.840 


.622 


.109 


14 


.39 


Z A 


1.050 


.824 


.113 


14 


.40 


l 


1.315 


1.048 


.134 


11% 


.51 


IX 


1.660 


1.380 


.140 


11% 


.54 


IX 


1.900 


1.610 


.145 


11% 


.55 


2 


2 375 


2.067 


.154 


11% 


.58 


2X 


2.875 


2.468 


.204 


8 


.89 


3 


3.500 


3.067 


.217 


8 


.95 


sX 


4.000 


3.548 


.226 


8 


1.00 


4 


4.500 


4.026 


.237 


8 


1.05 


4% 


5.000 


4.508 


.246 


8 


1.10 


5 


5.563 


5.045 


.259 


8 


1.16 


6 


6.625 


6.065 


.280 


8 


1.26 


7 


7.625 


7 023 


.301 


8 


1.36 


8 


8 625 


7.981 


.322 


8 


1.46 


9 


9.625 


8.937 


.344 


8 


1.57 


10 


10.750 


10.018 


.366 


8 


168 


11 


11.75 


11.000 


.375 


8 


1.78 


12 


12.75 


12.000 


.375 


8 


1.88 


13 


14 


13.25 


.375 


8 


2.09 


14 


15 


14.25 


.375 


8 


2.10 


15 


16 


15.25 


.375 


8 


2.20 



Taper of the thread is % inch to one foot. 

Pipe from X inch to 1 inch inclusive is butt welded and 
tested to 300 pounds per square inch. 

Pipe 1% inch and larger is lap welded and tested to 500 
pounds per square inch. 



TABLES 



597 



Table No. 37 — Length of Threads Cut on Bolts. 


Diameter 
of Bolt in 


LENGTH of bolts in inches. 


1 


1% 


2% 


2X 


sX 


4X 


8X 


Inches. 


to 


to 


to 


to 


to 


to 


to 




IX 


2 


2X 


3 


4 


8 


12 


X 


% 


X 


1 


1 


IX 


IX 




5 
T"S" 


X 


% 


1 


1 


IX 


IX 




X 


% 


1 


IX 


IX 


IX 


1% 


IX 


7 
T5" 


% 


1 


IX 


IX 


IX 


1% 


IX 


X 


% 


1 


IX 


IX 


1% 


IX 


1% 


A 


% 


1 


IX 


IX 


1% 


IX 


IX 


% 


1 


ix 


IX 


IX 


IX 


1% 


IX 


X 




IX 


IX 


IX 


1% 


1% 


2 


X 




IX 


IX 


IX 


IX 


2 


2X 


l 






IX 


2 


2X 


2X 


2% 


lX 








2X 


2X 


2% 


3 


lX 










2X 


3 


3X 



Bolts larger in diameter and longer than given in the table 
are threaded a length equal to three times their diameter. 



Table No. 38 — English or Whitworth Standard 
Pipe Threads. 



Nominal Inside 


Threads per 


Nominal Inside 


Threads per 


Diameter. 


Inch. 


Diameter. 


Inch. 


X 


28 


3 




X 


19 


3X 




X 


19 


4 




X 


14 


4X 




% 


14 


5 




1 


11 


6 




IX 


11 


7 




IX 


11 


8 


11 and 10 


2 
2X 


11 
11 


Larger than 8 


10 



598 



MACHINE SHOP PRACTICE 



Table No 


. 39 — Weight per Foot of Square and Round 


Iron Bars 


, Iron Weighing 480 Pounds 






per Cubic Foot. 






Thickness 


Weight of 


Weight of 


Thickness 


Weight of 


Weight of 


or 


Square Bar 


Round Bar 


or 


Square Bar 


Round Bar 


Diameter 


One Font 


One Foot 


Diameter 


One Foot 


One Foot 


in Inches. 


Long. 


Long. 


in Inches 


Long 


Long 


1-16 


.013 


.010 


2 1-16 


14.18 


11.14 


1-8 


.052 


.041 


1-8 


15.05 


11.82 


3-16 


.117 


.092 


3-16 


15.95 


12.53 


1-4 


.208 


.164 


1-4 


16.88 


13.25 


5-16 


.326 


.256 


5-16 


17.83 


14.00 


3-8 


.469 


.368 


3-8 


18.80 


14.77 


7-16 


.638 


.501 


7-16 


19.80 


15.55 


1-2 


.833 


.654 


1-2 


20.83 


16.36 


9-16 


1.055 


.828 


9-16 


21.89 


17.19 


5-8 


1.302 


1.023 


5-8 


22.97 


18.04 


11-16 


1.576 


1.237 


11-16 


24.08 


18.91 


3-4 


1.875 


1.473 


3-4 


25.21 


19.80 


13-16 


2.201 


1.728 


13-16 


26.37 


20.71 


7-8 


2.552 


2.004 


7-8 


27.55 


21.64 


5-16 


2.930 


2.301 


15-16 


28.76 


22.59 


1 


3.333 


2.618 


3 


30.00 


23.56 


1-V 


3.763 


2.955 


1-16 


31.26 


24.55 


1-8' 


) 4.219 


3.313 


1-8 


32.55 


25.57 


3-16 


4.701 


3.692 


3-16 


33.87 


26.60 


1-4 


5.208 


4.091 


1-4 


35.21 


27.65 


5-16 


5.742 


4.510 


5-16 


36.58 


28.73 


3-8 


6.302 


4.950 


3-8 


37.97 


29.82 


7-16 


6.888 


5.410 


7-16 


39.39 


30.94 


1-2 


7.500 


5.890 


1-2 


40.83 


32.07 


9-16 


8.138 


6.392 


9-16 


42.30 


33.23 


5-8 


8.802 


6.913 


5-8 


43.80 


34.40 


11-16 


9.492 


7.455 


11-16 


45.33 


35.60 


3-4 


10.21 


8.018 


3-4 


46.88 


36.82 


13-16 


19.95 


8.601 


13-16 


48.45 


38.05 


7-8 


11.72 


9.204 


7-8 


50.05 


39.31 


15-16 


12.51 


9.828 


15-16 


51.68 


40.59 


2 


13.33 


10.47 


4 


53.33 


41.89 



TABLES 



599 



Table No. 40 — Properties 


of Metals. 




Melting 

Point. 

Degrees 

Fahrenheit 


Weight 

in Lbs. 

Per 

Cubic 

Foot. 


Weight 
in Lbs. 

Per 
Cubic 
Inch. 


Tensile 
Strength in 

Lbs. Per 
Square Inch. 


Aluminum 


1140 


166.5 


.0963 


15000-30000 


Antimony 


810-1000 


421.6 


.2439 


1050 


Brass (average) 


1500-1700 


523.2 


.3027 


30000-45000 


Copper 


1930 


552. 


.3195 


30000-40000 


Gold (pure) 


2100 


1200.9 


.6949 


20380 


Iron, cast 


1900-2200 


450. 


.2604 


20000-35000 


Iron, wrought 


2700-2830 


480. 


.2779 


35000-60000 


Lead 


618 


709.7 


.4106 


1000-3000 


Mercury- 


39 


846.8 


.4900 




Nickel 


2800 


548.7 


.3175 




Silver (pure) 


1800 


655.1 


.3791 


40000 


Steel 


2370-2685 


489.6 


.2834 


50000-120000 


Tin 


475 


458.3 


.2652 


5000 


Zinc 


780 


436.5 


.2526 


3500 



Note, The wide variations in the tensile strength are 
due to the different forms and qualities of the metal tested. 
In the case of lead, the lowest strength is for lead cast in a 
mould, the highest for wire drawn after numerous workings 
of the metal. With steel it varies with the percentage of 
carbon used, which is varied according to the grade of steel 
required. Mercury becomes solid at 39 degrees below zero. 



600 



MACHINE SHOP PRACTICE 



STANDARD SCREW THREADS 



Table No. 41. — U. S. or Franklin Institute Standard. 


Formula: Flat — Pi ^ ch Pitch — . ..* 


8 Threads per In. 


Depth = Pitch x. 6495 


Diame- 


No.Thds. 


Diame- 


No.Thds 


Diame- 


No.Thds 


Diame- 


[No.Thds. 


ter. 


per Inch. 


ter. 


per Inch 


ter. 


per Inch. 


ter. 


per Inch. 


1-4 


20 


7-8 


9 


17-8 


5 


2 7-8 


3 1-2 


5-16 


18 


1 


8 


2 


41-2 


3 


3 1-2 


3-8 


16 


11-8 


7 


2 1-8 


41-2 


3 1-8 


3 1-2 


7-16 


14 


1 1-4 


7 


2 1-4 


4 1-2 


3 1-4 


3 1-2 


1-2 


13 


13-8 


6 


2 3-8 


4 


3 3-8 


3 1-4 


9-16 


12 


1 1-2 


6 


2 1-2 


4 


3 1-2 


3 1-4 


5-8 


11 


1 5-8 


5 1-2 


2 5-8 


4 


3 5-8 


3 1-4 


3-4 


10 1 3-4 


5 


2 3-4 


4 


3 3-4 


3 


Table No. 42.— V Standard. 


Formula: Depth = Pitch x 8660 Pitch—. 1 


Threads per in. 


Diame- 


No.Thds. 


Diame- 


No.Thds. 


Diame- 


No.Thds. 


Diame- 


No.Thds. 


ter. 
1-4 


per Inch. 


ter. 


per Inch. 


ter. 


per Ihch. 


ter. 


per Inch. 


20 


13-16 


10 


13-4 


5 


2 7-8 


4 


5-16 


18 


7-8 


9 


17-8 


41-2 


3 


3 1-2 


3-8 


16 


15-16 


9 


2 


41-2 


3 1-8 


3 1-2 


7-16 


14 


1 


8 


2 1-8 


4 1-2 


3 1-4 


3 1-2 


1-2 


12 


1 1-8 


7 


2 1-4 


41-2 


3 3-8 


3 1-4 


9-16 


12 


1 1-4 


7 


2 3-8 


4 1-2 


3 1-2 


3 1-4 


5-8 


11 


1 3-8 


6 


2 1-2 


4 


3 5-8 


3 1-4 


11-16 


11 


1 1-2 


6 


2 5-8 


4 


3 3-4 


3 


3-4 


10 


1 5-8 


5 


2 3-4 


4 


3 7-8 


3 


Table No. 43.— Whitworth Standard. 


Formula- Radius = Pitch x .1373 j 


>iVh — 1 


Depth = Pitch x .64033 


Threads per In. 


Diame- 


NoThds. 


Diame- 


No.Thds. 


Diame- 


No.Thds. 


Diame- 


No.Thds. 


ter. 


per Inch. 


ter. 


per Inch. 


ter. 


per Inch. 


ter. 


per Inch. 


1-4 


20 


13-16 


10 


13-4 


5 


2 7-8 


3 1-2 


5-16 


18 


7-8 


9 


17-8 


4 1-2 


3 


3 1-2 


3-8 


16 


15-16 


9 


2 


4 1-2 


3 1-8 


3 1-2 


7-16 


14 


1 


8 


2 1-8 


41-2 


3 1-4 


3 1-4 


1-2 


12 


1 1-8 


7 


2 1-4 


4 


3 3-8 


3 1-4 


9-16 


12 


1 1-4 


7 


2 3-8 


4 


3 1-2 


3 1-4 


5-8 


11 


1 3-8 


6 


2 1-2 


4 


3 5-8 


3 1-4 


11-16 


11 


1 1-2 


6 


2 5-8 


4 


3 3-4 


3 


3-4 


10 


1 5-8 


5 


2 3-4 


3 1-2 


3 7-8 


3 






TABLES 



601 



Table No. 44— Melting, Boiling and Freezing Points 
in Degrees Fahrenheit of Various Substances. 



Substance. 



Melts at 
Degrees 



Substance. 



Melts at 
Degrees 



Platinum 

Wrought-Iron 

Nickel 

Steel 

Cast-Iron 

Gold (pure) 

Copper 

Gun Metal 

Brass 

Silver (pure) 

Aluminum 



3080 
2830 
2800 
2600 
2200 
2100 
1930 
1960 
1900 
1800 
1140 



Antimony 

Zinc 

Lead 

Bismuth 

Tin 

Cadmium 

Sulphur 

Bees-Wax 

Spermaceti 

Tallow 

Mercury 



810 
780 
618 
476 
475 
442 
226 
151 
142 
72 
39 



Substance. 



Boils at 
Degrees 



Mercury 660 

Linseed Oil 600 

Sulphuric Acid 590 

Oil of Turpentine 560 

Nitric Acid 242 

Sea Water 213 

Fresh Water 212 



Substance. 



Freezes at 
Degrees 



Olive Oil 
FreshWater 
Vinegar 
Sea Water 
Turpentine 
Sulphuric Acid 



36 
32 
28 

27% 
14 
1 



602 



MACHINE SHOP PRACTICE 



Table No. 45 — Drill List for U. S. Standard 






Threads. 




Sizeo 


E No.of 


Sizeo 
Tap 
Drill. 


Size oJ 


No.of 


Size of 
Tap 
Drill. 


Size of No. of 


Size of 


Tap. 


Thds. 


Tap. 


Thds. 


Tap. 


Thds. 


Tap 
Drill. 


~%~ 


20 


3-16 


X 


10 


X 


IX 


5 


U* 


5-16 


18 


D 


X 


9 


47-64 n/ 8 


5 


m 


H 


16 


N 


l 


8 


27-32 2 


4^ 


1 23-32 


7-16 


14 


9r3 


W 


7 


61-64 2% 


*H 


1 27-32 


l A 


13 


13-32 


IX 


7 


1 5-64 2X 


4X 


1 31-32 


9-16 


1 12 


29-64 


ltt 


6 


111-64 2)4 


4 


2 1-16 


X 


11 


33-64 


IK 


6 

5^ 


119-64 2% 
1 25-64 


4 


2 3-16 


Table 


No. 46 — Machine Screw Tap Drills 




Size 

of 

Tap. 


Size of 
Drill for 


Size 
of 


Size 

of 

Tap. 


Size of 
Drill for 


Size 
of 


Size 

of 

Tap. 


Size of 
Drill for 


Size of 
Tap 
Drill. 


Body of 
Screw. 


Tap 
Drill. 


Body of 
Screw. 


Tap 
Drill. 


Boby of 
Screw. 


2-48 


44 


50 


9-28 


16 


28 


16-16 


I 


12 


2-56 


44 


49 


9-30 


16 


28 


16-18 


I 


8 


2-64 


44 


48 


9-32 


16 


26 


16-20 


I 


7 


3-40 


39 


49 


10-24 


11 


26 


17-16 


L 


8 


3-48 


39 


47 


10-30 


11 


24 


17-18 


L 


4 


3-56 


39 


45 


10-32 


11 


24 


17-20 


L 


3 


4-32 


33 


46 


11-24 


6 


21 


18-16 


19-64 


2 


4-36 


33 


44 


11-28 


6 


20 


18-18 


19-64 


2 


4-40 


33 


43 


11-30 


6 


19 


18-20 


19-64 


1 


5-30 


% 


43 


12-20 


7-32 


24 


19-16 


5-16 


1 


5-32 


% 


42 


12-22 


7-32 


20 


19-18 


5-16 


B 


5-36 


% 


41 


12-24 


7-32 


19 


19-20 


5-16 


G 


5-40 


% 


38 


12-28 


7-32 


18 


20-16 


P 


C 


6-30 


28 


38 


13-20 


15-64 


17 


20-18 


P 


E 


6-32 


28 


37 


13-22 


15-64 


17 


20-20 


P 


F 


6-36 


28 


36 


13-24 


15-64 


15 


22-16 


S 


H 


6-40 


28 


35 


14-20 


H 


15 


22-18 


S 


J 


7-28 


24 


34 


14-22 


% 


11 


24-14 


% 


L 


7-30 


24 


33 


14-24 


% 


10 


24-16 


% 


M 


7-32 


24 


32 


15-18 


F 


12 


24-18 




N 


8-24 


19 


31 


15-20 


F 


10 


26-14 


13-32 





8-30 


19 


31 


15-22 


F 


8 


26-16 


13-32 


P 


8-32 


19 


30 


15-24 


F 


7 


28-14 


7-16 


R 


9-24 


16 


30 








28-16 


7-16 


S 



TABLES 



603 



Table No. 47 — Drill List for V Thread Taps. 



Diameter 


Thds. 


Size 
of 


Diameter 


Thds. 


Size of 


Diameter 


Thds. 


' Tize of 


of Tap. 


per 
Inch. 


Tap 
Drill. 


of Tap. 


per 
Inch. 


Tap Drill. 


of Tap. 


per 
Inch. 


Tap Drill. 


3-32 


48 


49 


13-32 


16 


P 


15-16 


9 


25-32 


3-32 


56 


48 


13-32 


18 


21-64 


31-32 


9 


13-16 


3-32 


60 


47 


7-16 


14 


R 


1 


8 


53-64 


7-64 


32 


49 


7-16 


16 


S 


1 1-32 


8 


55-64 


7-64 


36 


48 


15-32 


14 


3-8 


1 1-16 


8 


57-64 


7-64 


40 


46 


15-32 


16 


W 


1 3-32 


8 


59-64 


1-8 


32 


44 


1-2 


12 


25-64 


1 1-8 


7 


59-64 


1-8 


36 


42 


1-2 


13 


X 


1 1-8 


8 


61-64 


1-8 


40 


41 


1-2 


14 


13-32 


1 5-32 


7 


61-64 


9-64 


30 


40 


17-32 


12 


27-64 


1 5-32 


8 


63-64 


9-64 


32 


38 


17-32 


13 


27-64 


1 3-16 


7 


63-64 


9-64 


36 


37 


17-32 


14 


7-16 


1 3-16 


8 


1 1-64 


5-32 


30 


33 


9-16 


12 


29-64 


1 7-32 


7 


1 1-64 


5-32 


32 


32 


9-16 


14 


15-32 


1 7-32 


8 


1 3-64 


5-32 


36 


31 


19-32 


12 


31-64 


1 1-4 


7 


1 3-64 


3-16 


24 


29 


19-32 


14 


1-2 


1 9-32 


7 


1 5-64 


3-16 


30 


26 


5-8 


10 


31-64 


1 5-16 


7 


1 7-64 


3-16 


32 


27 


5-8 


11 


1-2 


1 11-32 


7 


1 9-64 


7-32 


24 


20 


5-8 


12 


15-32 


1 3-8 


6 


1 1-8 


7-32 


30 


16 


21-32 


10 


33-64 


1 13-32 


6 


1 5-32 


7-32 


32 


14 


21-32 


11 


17-32 


1 7-16 


6 


1 3-16 


1-4 


18 


17 


21-32 


12 


35-64 


1 15-32 


6 


1 7-32 


1-4 


20 


14 


3-4 


10 


39-64 


1 1-2 


6 


1 17-64 


1-4 


24 


8 


3-4 


11 


5-8 


1 17-32 


6 


1 19-64 


9-32 


18 


1 3 
^"4 


3-4 


12 


11-16 


1 5-8 


5 


1 21-64 


9-32 


20 


3 


25-32 


10 


45-64 


1 21-32 


5 


1 23-64 


5-16 


16 


1 


25-32 


11 


45-64 


1 3-4 


5 


1 29-64 


5-16 


18 


C 


25-32 


12 


23-32 


1 25-32 


5 


1 31-64 


5-16 


20 


E 


13-16 


10 


43-64 


1 13-16 


5 


1 33-64 


11-32 


16 


F 


27-32 


10 


45-64 


1 27-32 


5 


1 35-64 


11-32 


18 


1 7 
"6T 


7-8 


9 


23-32 


1 7-8 


4|- 


1 35-64 


3-8 


14 


K 


7-8 


10 


47-64 


1 29-32 


4^ 


1 37-64 


3-8 


16 


M 


29-32 


9 


3-4 


1 15-16 


4^r 


1 39-64 


3-8 


18 


1 9 
S"4 


29-32 


10 


49-64 


1 31-32 


4^ 


1 41-64 


13-32 


14 


N 








2 


4 


1 43-64 



604 



MACHINE SHOP PRACTICE 



Table No. 48 — Proportionate Weight op Castings 


to Weight op Wood Patterns. 


A Pattern Weighing 














One Pound Made 
of 

(Less Weight of 


a 
o 
u 
•— • 

92 

O 


GO 
00 

e3 
u 

« 


u 

a> 

p. 

G 
O 

o 


a3 

N 

a 
o 

s-c 

ffl 


"3 

a> 

g 

oq 


*3 

a 


Core Prints). 














Pine or Fir 


16 


15.8 


16.7 


16.3 


17.1 


13.5 


Oak 


9 


10.1 


10.4 


10.3 


10.9 


8.6 


Beech 


9.7 


10.9 


11.4 


11.3 


11.9 


9.1 


Linden 


13.4 


15.1 


16.7 


15.5 


16.3 


12.9 


Pear 


10.2 


11.5 


11.9 


11.8 


12.4 


9.8 


Birch 


10.6 


11.9 


12.3 


12.2 


12.9 


10.2 


Alder 


12.8 


14.3 


14.9 


14.7 


15.5 


12.2 


Mahogany 


11.7 


13.2 


13.7 


13.5 


14.2 


11.2 


Brass 


0.85 


0.95 


0.99 


0.98 


1.0 


0.81 



To ascertain the approximate weight of a casting from the 
weight of the pattern: 

Multiply the weight of the pattern (less the weight of the 
core prints) by the number in the table corresponding to 
the material of which the pattern is made and the metal 
which is to be used for the casting. The result will be the 
approximate weight of the casting in pounds. 



TABLES. 



605 



Table No. 49 — Letter Sizes of 


Drills. 


Diameter Inches. 


Decimals of 
1 Inch. 


Diameter Inches. 


Decimals of 
1 Inch. 


A if 


.234 


N 


.302 


B 


.238 


OA 


.316 


C 


.242 


P*i 


.323 


D 


.246 


Q 


.332 


EX 


.250 


XI 32 


.339 


F 


.257 


s 


.348 


G 


.261 


rp 23 

X "ST 


.358 


XT 1 7 


.266 


U 


.368 


I 


.272 


v% 


.377 


J 


.277 


w» 


.386 


K ^y 


.281 


X 


.397 


L 


.290 


V 1 3 


.404 


Mil 


.295 


z 


.413 



Table No. 50 — Sizes op 


Tap Drills. 


Tap 


Threads per 


Drill for V 


Drill for U. S. 


Drill for 


Diameter. 


Inch. 


Thread. 


Standard. 


Whitworth. 


X 


16, 18, 20 


5 5 11 
^Y "3"^" "54 


3-16 


3-16 


& 


16, 18, 20 


3 13 13 
T6" ST "BT 






5 


16, 18 


7 15 
"3~2" "ST 


1-4 


15-64 


1 1 


16, 18 


/4 T4 






% 


14, 16, 18 


X/ 9 9 
/4 ¥T ¥2" 


9-32 


9-32 


1 3 


14, 16, 18 


19 2 1 2 1 
"5~4 "5T "BT 






tV 


14, 16 


2 1 11 

"6"4 ¥Y 


11-32 


11-32 


1 5 


14, 16 


2¥ 3/ 
¥T /8 






X 


12, 13, 14 


3 / 2 5 2 5 
/8 Ti" "5T 


13-32 


3-8 


A 


12, 14 


7 29 
T¥ "ST 


7-16 




k 


10, 11, 12 


u X X 


1-2 


1-2 


1 1 

% 


11, 12 
10, 11, 12 


9 9 
19 6/ 5/ 

T2" '8 /8 


5-8 


5-8 


1 3 


10 


21 






% 


9, 10 


4 5 23 
TT ~5Y 


23-32 


23-32 


n 


9 


49 
T4 






i 


8 


1 3 
TT 


27-32 


27-32 



606 



MACHINE SHOP PRACTICE 



Tabi,e No. 51. — Weight and Area of Square and Round 


Steee, 


and the Circumference of Round Bars. 


Steel weighing 490 pounds per cubic foot. 




Thickness 


Weight 


Weight 


Area of 


Area of 


Circumfer- 


or 


of 


of 


Square 


Round 


ence of 


Diameter 


Square 


Round 


Bar in 


Bar in 


Round 


in 


Bar 


Bar 


Square 


Square 


Bar in 


Inches. 


1 ft. long 


1 ft. long. 


Inches. 


Inches. 


Inches. 


3-16 


.120 


.094 


.0352 


.0276 


.5890 


1-4 


.213 


.167 


.0625 


.0491 


.7854 


5-16 


.332 


.261 


.0977 


.0767 


.9817 | 


3-8 


.478 


.375 


.1406 


.1104 


1.1781 


7-16 


.651 


.511 


.1914 


.1503 


1.3744 ; 


1-2 


.851 


.668 


.2500 


.1963 


1.5708 


9-16 


1.076 


.845 


.3164 


.2485 


1.7671 


5-8 


1.329 


1.044 


.3906 


.3068 


1.9635 


11-16 


1.608 


1.263 


.4727 


.3712 


2.1598 


3-4 


1.914 


1.503 


.5625 


.4418 


2.3562 


13-16 


2.246 


1.764 


.6602 


.5185 


2,5525 


7-8 


2.605 


2.046 


.7656 


.6013 


2.7489 


15-16 


2.990 


2.348 


.8789 


.6903 


2.9452 


1 


3.402 


2.672 


1.0000 


.7854 


3.1416 


1-16 


3.841 


3.017 


1.1289 


.8866 


3.3379 


1-8 


4.306 


3.382 


1.2656 


.9940 


3.5343 


3-16 


4.798 


3.768 


1.4102 


1.1075 


3.7306 


1-4 


5.316 


4.175 


1.5625 


1.2272 


3.9270 


5-16 


5.861 


4.603 


1.7227 


1.3530 


4.1233 


3-8 


6.432 


5.052 


1.8906 


1.4849 


4.3197 


7-16 


7.030 


5.521 


2.0664 


1.6230 


4.5160 


1-2 


7.655 


6.012 


2.2500 


1.7671 


4.7124 


9-16 


8.306 


6.524 


2.4414 


1.9175 


4.9087 


5-8 


8.984 


7.056 


2.6406 


2.0739 


5.1051 


11-16 


9.688 


7.609 


2.8477 


2.2365 


5.3014 


3-4 


10.419 


8.183 


3.0625 


2.4053 


5.4978 


13-16 


11.177 


8.778 


3.2852 


2.5802 


5.6941 


7-8 


11.961 


9.394 


3.5156 


2.7612 


5.8905 


15-16 


12.772 


10.031 1 


3.7539 


2.9483 


6.0868 j 



TABLES 



607 



Tabee No. 51. — Weight and Area of Square and Round 


Steee, 


and the Circumference of 


Round Bars. 


Steel weighing 490 pounds per cubic foot. 




Thickness 

or 

Diameter 

in 

Inches. 


Weight 

of 

Square 

Bar 

1 ft. long. 


Weight 

of 

Round 

Bar 

1 ft. long. 


Area of 

Square 

Bar 

in Square 

Inches. 


Area of 

Round 

Bar 

in Square 

Inches. 


Circumfer- 
ence of 
Round 
Bar in 
Inches. 


2 


13.61 


10.69 


4.0000 


3.1416 


6.2832 


1-16 


14.47 


11.36 


4.2539 


3.3410 


6.4795 


1-8 


15.36 


12.06 


4.5136 


3.5466 


6.6759 


3-16 


16.28 


12.79 


4.7852 


3.7583 


6.8722 


1-4 


17.22 


13.52 


5.0625 


3.9761 


7.0686 


5-16 


18.19 


14.29 


5.3477 


4.2000 


7.2649 


3-8 


19.19 


15.07 


5.6406 


4.4301 


7.4613 


7-16 


20.21 


15.87 


5.9414 


4.6664 


7.6576 


1-2 


21.26 


16.70 


6.2500 


4.9087 


7.8540 


9-16 


22.34 


17.55 


6.5664 


5.1572 


8.0503 


5-8 


23.44 


18.41 


6.8906 


5.4119 


8.2467 


11-16 


24.57 


19.30 


7.2227 


5.6727 


8.4430 


3-4 


25.73 


20.21 


7.5625 


5.9396 


8.6394 


13-16 


26.91 


21.14 


7.9102 


6.2126 


8.8357 


7-8 


28.12 


22.09 


8.2656 


6.4918 


9.0321 


15-16 


29.36 


23.06 


8.6289 


6.7771 


9.2284 


3 


30.62 


24.05 


9.0000 


7.0686 


9.4248 


1-16 


31.91 


25.06 


9.3789 


7.3662 


9.6211 


1-8 


33.23 


26.10 


9.7656 


7.6699 


9.8175 


3-16 


34.57 


27.15 


10.160 


7.9798 


10.014 


1-4 


35.94 


28.23 


10.563 


8.2958 


10.210 


5-16 


37.33 


29.32 


10.973 


8.6179 


10.407 


3-8 


38.75 


30.43 


11.391 


8.9462 


10.603 


7-16 


40.20 


31.57 


11.816 


9.2806 


10.799 


1-2 


41.68 


32.74 


12.250 


9.6211 


10.996 


9-16 


43.17 


33.91 


12.691 


9.9678 


11.192 


5-8 


44.71 


35.12 


13.141 


10.321 


11.388 


11-16 


46.26 


36.33 


13.598 


10.680 


11.585 


3-4 


47.84 


37.57 


14.063 


11.045 


11.781 


13-16 


49.45 


38.84 


14.535 


11.416 


11.977 


7-8 


51.09 


40.13 


15.016 


11.793 


12.174 


15-16 


52.75 


41.43 


15.504 


12.177 


12.370 


4 


54.45 


42.77 


16.00 


12.566 


12.566 



608 



MACHINE SHOP PRACTICE 





Table No. 


52 — Size and Weight of Hot Pressed 




Hexagon Nuts United States Standard Sizes. 


1 


Weights and 


sizes are for unfinished Nuts. 




Width 


Thick- 






Size 


Weight 


Number 




over 


ness in 


Size of Hole. 


of 


of 100 


of Nuts in 




Flats. 


Inches. 






Bolt. 


Nuts. 


100 Lbs. 




1-2 


1-4 


0.185 


tV scant. 


X 


1.3 


7615 




19-32 


5-16 


0.240 


X " 


5 


1.9 


5200 




11-16 


3-8 


0.294 


19 " 


7k 


3.3 


3000 




25-32 


7-16 


0.344 


l l 


7 


5.0 


2000 




7-8 


1-2 


0.400 


if scant. 


X 


7.0 


1430 




31-32 


9-16 


0.454 


89 


9 


9.1 


1100 


1 


1-16 


5-8 


0.507 


X full. 


% 


13.5 


740 


1 


1-4 


3-4 


0.620 


X scant. 


X 


22.2 


450 


1 


7-16 


7-8 


0.731 


H scant. 


% 


32.4 


309 


1 


5-8 


1 


0.837 


27 H 
ST 


1 


46.3 


216 


1 


13-16 


11-8 


0.940 


f| full. 


IX 


67.6 


148 


2 




11-4 


1.065 


ItV " 


IX 


90.1 


111 


2 


3-16 


13-8 


1.160 


1A full. 


1% 


117.5 


85 


2 


3-8 


11-2 


1.284 


i "9- << 


iy 2 


147.1 


68 


2 


9-16 


15-8 


1.389 


lfr scant. 


1% 


178.6 


56 


2 


3-4 


13-4 


1.491 


1% " 


1% 


250.0 


40 


2 


15-16 


17-8 


1.616 


1% scant. 


1% 


285.7 


35 


3 


1-8 


2 


1.712 


123 " 


2 


344.8 


29 


3 


5-16 


2 1-8 


1.836 


m " 


2% 


384.6 


26 


3 


1-2 


2 1-4 


1.962 


m " 


2X 


434.8 


23 



TABLES 



609 



3 
1 


Table No. 


53 — Size and Weight op Hot Pressed 


) 

1 


Square Nuts United States 


I Standard Sizes. 


Weights and sizes are for unfinished Nuts. 








Thick- 






Size 


Weight 


Number 


Wid 


ness in 


Size c 


of 


of 100 


of Nuts in 






Inches. 






Bolt. 


Nuts. 


100 Lbs. 




1-2 


1-4 


0.185 


tV scant. 


X 


1.4 


7270 




19-32 


5-16 


0.240 


1/ n 

74 


5 


2.2 


4700 




11-16 


3-8 


0.294 


19 " 
6T 


3 / 
/8 


4.3 


2330 




25-32 


7-16 


0.344 


l l 


TB" 


6.1 


1630 




7-8 


1-2 


0.400 


if scant. 


X 


9.0 


1120 




31-32 


9-16 


0.454 


2 9 
"6T 


9 
T5" 


11.2 


890 


1 


1-16 


5-8 


0.507 


X full. 


X 


15.6 


640 


1 


1-4 


3-4 


0.620 


% scant. 


% 


26.3 


380 


1 


7-16 


7-8 


0.731 


■It scant. 


% 


35.7 


280 


1 


5-8 


1 


0.837 


27 " 
X2" 


1 


58.8 


170 


1 


13-16 


1 1-8 


0.940 


il full. 


IX 


76.9 


130 


2 




1 1-4 


1.065 


-ii " 

-Ltt 


IX 


104.2 


96 


2 


3-16 


13-8 


1.160 


lfV full. 


1% 


142.8 


70 


2 


3-8 


11-2 


1.284 




IX 


172.4 


58 


2 


9-16 


15-8 


1.389 


Iff scant. 


lX 


227.3 


44 


2 


3-4 


13-4 


1.491 


IX " 


1% 


294.1 


34 


2 


15-16 


17-8 


1.616 


1% scant. 


IX 


370.4 


27 


3 


1-8 


2 


1.712 


123 " 


2 


416.7 


24 


3 


5-16 


2 1-8 


1.836 


-127 " 
J -Ff 


2X 


500.0 


20 


3 


1-2 


2 1-4 


1.962 


-131 " 


2X 


588.2 


17 



610 



MACHINE SHOP PRACTICE 



Table No. 


54- 


* 
-Weight per Foot of Fl&t Bar Steel. 


Steel weighing 490 pounds per squa re foot. 








Width in Inches. 


Thick- 
ness in 
Inches 
































1 


11-4 


1 1-2 


1M 


2 


2 1-4 


2 1-2 


3 


3 1-2 


4 


3-16 


.638 


.797 


.957 


1.11 


1.28 


1.44 


1.59 


1.91 


2.23 


2.55 


1-4 


..850 


1.06 


1.28 


1.49 


1.70 


1.91 


2.12 


2.55 


2.98 


3.40 


5-16 


1.06 


1.33 


1.59 


1.86 


2.12 


2.39 


2.65 


3.19 


3.72 


4.25 


- 3-8 


1.28 


1.59 


1.92 


2.23 


2.55 


2.87 


3.19 


3.83 


4.47 


5.10 


7-16 


1.49 


1.86 


2.23 


2.60 


2.98 


3.35 


3.73 


4.46 


5.20 


5.95 


1-2 


1.70 


2.12 


2.55 


2.98 


3.40 


3.83 


4.25 


5.10 


5.95 


6.80 


9-16 


1.92 


2.39 


2.87 


3.35 


3.83 


4.30 


4.78 


5.74 


6.70 


7.65 


5-8 


2.12 


2.65 


3.19 


3.72 


4.25 


4.78 


5.31 


6.38 


7.44 


8.50 


11-16 


2.34 


2.92 


3.51 


4.09 


4.67 


5.26 


5.84 


7.02 


8.18 


9.35 


3-4 


2.55 


3.19 


3.83 


4.47 


5.10 


5.75 


6.38 


7.65 


8.93 


10.20 


13-16 


2.76 


3.45 


4.14 


4.84 


5.53 


6.21 


6.90 


8.29 


9.67 


11.05 


7-8 


2.98 


3.72 


4.47 


5.20 


5.95 


6.69 


7.44 


8.93 


10.41 


11.90 


15-16 


3.19 


3.99 


4.78 


5.58 


6.38 


7.18 


7.97 


9.57 


11.16 


12.75 


1 


3.40 


4-25 


5.10 


5.95 


6.80 


7.65 


8.50 


10.20 


11.90 


13.60 


1 1-16 


3.61 


4.52 


5.42 


6.32 


7.22 


8.13 


9.03 


10.84 


12.15 


14.45 


1 1-8 


3.83 


4.78 


5.74 


6.70 


7.65 


8.61 


9.57 


11.48 


13.39 


15.30 


1 3-16 


4.04 


5.05 


6.06 


7.07 


8.08 


9.09 


10.10 


12.12 


14.13 


16.15 


1 1-4 


4.25 


5.31 


6.38 


7.44 


8.50 


9.57 


10.63 


12.75 


14.87 


17.00 


1 5-16 


4.46 


5.58 


6.69 


7.81 


8.93 


10.04 


11.16 


13.39 


15.62 


17.85 


1 3-8 


4.67 


5.84 


7.02 


8.18 


9.35 


10.52 


11.69 


14.03 


16.36 


18.70 


1 7-16 


4.89 


6.11 


7.34 


8.56 


9.78 


11.00 


12.22 


14.66 


17.10 


19.55 


1 1-2 


5.10 


6.38 


7.65 


8.93 


10.20 


11.48 


12.75 


15.30 


17.85 


20.40 


1 9-16 


5.32 


6.64 


7.97 


9.30 


10.63 


11.65 


13.28 


15.94 


18.60 


21.25 


1 5-8 


5.52 


6.90 


8.29 


9.67 


11.05 


12.43 


13.81 


16.58 


19.34 


22.10 


1 11-16 


5.74 


7.17 


8.61 


10.04 


11.47 


12.91 


14.34 


17.22 


20.08 


22.95 


1 3-4 


5.95 


7.44 


8.93 


10.42 


11.90 


13.40 


14.88 


17.85 


20.83 


23.80 


1 13-16 


6.16 


7.70 


9.24 


10.79 


12.33 


13.86 


15 40 


18.49 


21.57 


24.65 


1 7-8 


6.38 


7.97 


9.57 


11.15 


12.75 


14.34 


15 94 


19.13 


22.31 


25.50 


1 15-16 


6.59 


8.24 


9.88 


11.53 


13.18 


14.83 


16 47 


19.77 


23.06 26.35 


2 


6.80 


8.50 


10.20 


11.90 


13.60 


15.30 


17 00 


20.40 


23.80 


27.20 



TABLES 



611 



Table No. 55 — Weight per Foot of Flat Bar Iron. 




WIDTH IN INCHES. 


Thick 




ness. 


1 


1% 


IX 


1% 
.74 


2 


2X 


2% 


3 


3% | 4 


% 


.42 


.53 


.63 


.84 


.95 1.05 


1.26 


1.47 1 1.68 


X 


.84 


1.05 


1.26 


1.47 


1.68 


1.90 2.11 


2.53 


2.95 | 3.37 


% 


1.26 


1.58 


1.90 


2.21 


2.53 


2.84 


3.16 


3.79 


4.42 ! 5.05 


X 


1.68 2.11 


2.53 


2.95 


3.37 


3.79 


4.21 


5.05 


5.89 6.74 


% 


2.11i2.63 


3.16 


3.68 


4.21 


4.74 


5.26 


6.32 


7.37 


8.42 


% 


2.53 3.16 


3.79 


4.42 


5.05 


5.68 


6.32 


7.58 


8.84 


10.10 


% 


2.95J3.68 


4.42 


5.16 


5.89 


6.83 


7.37 


8.84 


10.32 


11.79 


1 


3.37 4.21 


5.05 


5.89 


6.74 


7.58 


8.42 


10.10 


11.79 


13.47 



Plate iron weighs 40 pounds per square foot, 1 inch thick. 
Hence, a square foot weighs 10 pounds if % inch thick, 
5 pounds if % inch thick, etc. 

To find the weight of round iron, per square foot in length: 
Square the diameter, expressed in quarter inches and divide 
by 6. 

Thus, a 1% inch rod weighs 5 X 5 = 25, 25 -*- 6 = A\ pounds 
per foot. 

To find the weight of square or flat iron, per yard in length: 
Multiply the area of the cross section by 10. 

Thus, a bar 2 by % has an area of % of a square inch, and 
consequently weighs % X 10 = 7X pounds per yard. 

To find the tensile strength of round iron: Square the 
diameter, expressed in quarters of an inch, the result will be 
its approximate tensile strength in tons. 

Thus, a rod 1 quarter inch in diameter will sustain 1 ton; 
2 quarters, 4 tons; 3 quarters 9 tons; 4 quarters, or 1 inch, 
16 tons. 

If the rod is square, and of the same diameter as the round 
bar, it will carry about 25 per cent more, hence, a bar 1 inch 
square will sustain about 20 tons. 



612 



MACHINE SHOP PRACTICE 



Table No. 56 — Wire Gauges in use in the r 




United States. 






O bo 

ll 

So; 


a3 

03 

os OG 


o . 

bo m 

£gq 

5 


O .S 
0*V 

^y o 


<D 

r-t 

,-h bo 
03 3 

:fi os 

&° 
s 


s . 

GO a> 
3D 


T3 

u 

03 . 

§* 
P 


^03 

0£ 


000000 








.464 




.46875 


000000 


00000 








.432 




.4375 


00000 


0000 


.46 


.454 


.3938 


.400 




.40625 


0000 


000 


.40964 


.425 


.3625 


.372 




.375 


000 


00 


.3648 


.38 


.3310 


.348 




.34375 


00 





.32486 


.34 


.3065 


.324 




.3125 





1 


.2893 


.3 


.2830 


.300 


.227 


.28125 


1 


2 


.25763 


.284 


.2625 


.276 


.219 


.265625 


2 


3 


.22942 


.259 


.2437 


.252 


.212 


.25 


3 


4 


.20431 


.238 


.2253 


.232 


.207 


.234375 


4 


5 


.18194 


.22 


.2070 


.212 


.204 


.21875 


5 


6 


.16202 


.203 


.1920 


.192 


.201 


.203125 


6 


7 


.14428 


.18 


.1770 


.176 


.199 


.1875 


7 


8 


.12849 


.165 


.1620 


.160 


.197 


.171875 


8 


9 


.11443 


.148 


.1483 


.144 


.194 


.15625 


9 


10 


.10189 


.134 


.1350 


.128 


.191 


.140625 


10 


11 


.090742 


.12 


.1205 


.116 


.188 


.125 


11 


12 


.080808 


.109 


.1055 


.104 


.185 


.109375 


12 


13 


.071961 


.095 


.0915 


.092 


.182 


.09375 


13 


14 


.064084 


.083 


.0800 


.080 


.180 


.078125 


14 


15 


.057068 


.072 


.0720 


.072 


.178 


.0703125 


15 


16 


.05082 


.065 


.0625 


.064 


.175 


.0625 


16 


17 


.045257 


.058 


.0540 


.056 


.172 


.05625 


" i 



TABLES 



613 



Table No. 56 Continued- 


-Wire Gauges in use in the 




United States. 






o be 


a> 

v - 

c > 


u 

J* 

P 


3 = 53 

•-- c 


-~ 


09 

si 

CO 


03 . 


Number ot 

Wire Gauge. 


18 


.040303 


.049 


.0475 


.048 


.168 


.05 


18 


19 


.03589 


.042 


.0410 


.040 


.164 


.04375 


19 


20 


.031961 


.035 


.0348 


.036 


.161 


.0375 


20 


21 


.028462 


.032 


.03175 


.032 


.157 


.034375 


21 


22 


.025347 


.028 


.0286 


.028 


.155 


.03125 


22 


23 


.022571 


.025 


.0258 


.024 


.153 


.028125 


23 


24 


.0201 


.022 


.0230 


.022 


.151 


.025 


24 


25 


.0179 


.02 


.0204 


.020 


.148 


.021875 


25 


26 


.01594 


.018 


.0181 


.018 


.146 


.01875 


26 


27 


.014195 


.016 


.0173 


.0164 


.143 


.0171875 


27 


28 


.012641 


.014 


.0162 


.0149 


.139 


.015625 


28 


29 


.011257 


.013 


.0150 


.0136 


.134 


.0140625 


29 


30 


.010025 


.012 


.0140 


.0124 


.127 


.0125 


30' 


31 


.008928 


.01 


.0132 


.0116 


.120 


.0109375 


31 


32 


.00795 


,009 


.0128 


.0108 


.115 


.01015625 


32 


33 


.00708 


.008 


.0118 


.0100 


.112 


.009375 


33 


34 


.006304 


.007 


.0104 


.0092 


.110 


.00859375 


34 


35 


.005614 


.005 


.0095 


.0084 


.108 


.0078125 


35 


36 


.005 


.004 


.0090 


.0076 


.106 


.00703125 


36 


37 


.004453 






.0068 


.103 


.006640625 


37 


38 


.003965 






.0060 


.101 


.00625 


38 


39 


.003531 






.0052 .099 




39 


40 


.003144 






.0048 .097 




40 



614 



MACHINE SHOP PRACTICE 





Table No 


. 57 — Weight op Sheet Iron and 






Steel 


per Square Foot. 






Thickness by 
Birmingham Gauge. 


Thickness by America] 
(Brown and S — rpc s) Ga 


3 

uge. 

ht in 
nds. 






Weight in 
Pounds. 






Wot 

Pov 


No. of 
Gauge. 


Thickness 
in Inches. 






No. of 
Gauge. 


Thickness 
in Inches. 


















Iron. 


Steel. 






Iron. 


SteeL 


0000 


.454 


18.16 


18.52 


0000 


.46 


18.40 


18.77 


000 


.425 


17.00 


17.34 


000 


.4096 


16.38 


16.71 


00 


.38 


15.20 


15.30 


00 


.3648 


14.59 


14.88 





.34 


13.60 


13.87 





.3249 


13.00 


13.26 


1 


.3 


12.00 


12.24 


1 


.2893 


11.57 


11.80 


2 


.284 


11.36 


11.59 


2 


.2576 


10.30 


10.51 


3 


.259 


10.36 


10.57 


3 


.2294 


9.18 


9.36 


4 


.238 


9.52 


9.71 


4 


.2043 


8.17 


8.34 


5 


.22 


8.80 


8.98 


5 


.1819 


7.28 


7.42 


6 


.203 


8.12 


8.28 


6 


.1620 


6.48 


6.61 


7 


.18 


7.20 


7.34 


7 


.1443 


5.77 


5.89 


8 


.165 


6.60 


6.73 


8 


.1285 


5.14 


5.24 


9 


.148 


5.92 


6.04 


9 


.1144 


4.58 


4.67 


10 


.134 


5.36 


5.47 


10 


.1019 


4.08 


4.16 


11 


.12 


4.80 


4.90 


11 


.0907 


3.63 


3.70 


12 


.109 


4.36 


4.45 


12 


.0808 


3.23 


3.30 


13 


.095 


3.80 


3.88 


13 


.0720 


2.88 


2.94 


14 


.083 


3.32 


3.39 


.14 


.0641 


2.56 


2.62 


15 


.072 


2.88 


2.94 


15 


.0571 


2.28 


2.33 


16 


.065 


2.60 


2.65 


16 


.0508 


2.03 


2.07 


17 


.058 


2.32 


2.37 


17 


.0453 


1.81 


1.85 


18 


.049 


1.96 


2.00 


18 


.0403 


1.61 


1.64 


19 


.042 


1.68 


1.71 


19 


.0359 


1.44 


1.46 


20 


.035 


1.40 


1.43 


20 


.0320 


1.28 


1,31 



TABLES 



615 



Table No. 57 Continued- 


—Weight of Sheet Iron 




and Steel per 


Square Foot. 




Thickness by 
Birmingham Gauge. 


Thickness by American 
(Brown and Sharpe's) Gauge. 






Weight in 
Pounds. 






Weight in 
Pounds. 


No. of 

Gauge. 


Thickness 
in Inches. 




No. of 
Gauge. 


Thickness 
in Inches. 
















Iron. 


Steel. 






Iron. 


Steel. 


21 


.032 


1.28 


1.31 


21 


.0285 


1.14 


1.16 


22 


.028 


1.12 


1.14 


22 


.0253 


1.01 


1.03 


23 


.025 


1.00 


1.02 


23 


.0226 


.904 


.922 


24 


.022 


.88 


.898 


24 


.0201 


.804 


.820 


25 


.02 


.80 


.816 


25 


.0179 


.716 


.730 


26 


.018 


.72 


.734 


26 


.0159 


.636 


.649 


27 


.016 


.64 


.653 


27 


.0142 


.568 


.579 


28 


.014 


.56 


.571 


28 


.0126 


.504 


.514 


29 


.013 


.52 


.530 


29 


.0113 


.452 


.461 


30 


.012 


.48 


.490 


30 


.0100 


.400 


.408 


31 


.01 


.40 


.408 


31 


.0089 


.356 


.363 


32 


.009 


.36 


.367 


32 


.0080 


.320 


.326 


33 


.008 


.32 


.326 


33 


.0071 


.284 


.290 


34 


.007 


.28 


.286 


34 


.0063 


.252 


.257 


35 


.005 


.20 


.204 


35 


.0056 


.224 


.228 





Iron. 


Steel. 


Specific gravity. 


7.7 


7.854 


Weight per cubic foot. 


480. 


489.6 


Weight per cubic inch. 


.2778 


.2833 



As there are many gauges in use differing from each other, 
orders for sheets should always state the weight per square 
foot, or the thickness in thousandths of an inch. 



616 



MACHINE SHOP PRACTICE 



Table No. 


58 — Allowances for 
Force Fits. 


Running and 


Running 


Fits. 


Force Fits. 


Diam. of 
Bearing. 
1 


Diam. of 

Shaft. 
.999 


Diam. of 
Hole. 
1 


Diam. of 
Shaft. 
1.001 


2 


. . . 1.998 


2 


2.003 


3 


. . . 2.997 


3 


3.005 


4 


. . . 3.9965 


4 


4.006 


5 


. . . 4.9963 


5 


5.007 


6 


. . . 5.996 


6 


6.008 


7 


. . . 6.9958 


7 


7.0085 


8 


... 7.9958 


8 

9 


8.009 

9.01 


9 


. . . 8.9957 


10 


. . . 9.9956 


10 


10.0105 


11 


... 10.9955 


11 


11.011 


12 


. . . 11.9954 


12 


12.0115 


13 


. . . 12.9953 


13 

14 


13.012 

14.013 


14 


... 13.9952 


15 


... 14.9951 


15 

16 


15.014 

16.0145 


16 


... 15.995 


17 


. . . 16.9949 


17 

18 

19 

20 


17.015 

18.0155 

19.016 

20.017 


18 


. 17.9948 


19 

20 


... 18.9947 





Drive fits allowances are one-half that of force fits. 



INDEX 



ARITHMETIC: r3ge 

An integer 9 

An odd number 9 

An even number 9 

Factors of numbers 9 

A prime number 9 

An exact divisor . : 9 

The greatest common divisor 9 

A multiple 9 

The least common multiple 9 

Addition . . . . . 10 

Subtraction 10 

Multiplication 11 

Division VI 

Algebraic signs and symbols 12 

Decimal fractions 14 

Addition of decimals 14 

Substraction of decimals 15 

Multiplication of decimals 15 

To reduce a vulgar fraction to a decimal 16 

Reading decimals 17 

Roots of numbers 18 

To extract the square root of a vulgar fraction 19 

To extract the cubic root of a number 19 

Reciprocals . 23 

Logarithms of numbers 34 

PRACTICAL GEOMETRY: 

To bisect a straight line < , 43 

To erect a perpendicular at the end of a straight line 43 

To divide a straight line into any number of equal parts.. 43 

To find the length of an arc of a circle . . . . . 42 

To draw radial lines from the circumference of a circle.. 44 

617 



618 INDEX 

Page 

To describe anr x <3gular polygon in a circle. 44 

To cut a beam of the strongest shape from a circular sec- 
tion 45 

To develop the surface of a cone or a frustum of a cone. .. 46 
To construct a square upon a straight line of given length 46 
To construct a square equal in area to a given triangle . . 46 
To construct a square equal in area to a given rectangle.. 47 
To find the length of rectangle equal in area to a given 

square, when the width is given 47 

To divide any triangle into two parts of equal area 47 

To inscribe a circle of the greatest possible diameter in a 

given triangle 48 

To construct a rectagle of the greatest possible area in a 

given triangle - 48 

To construct a rectangle equal in area to a given triangle.. 49 
To construct a triangle equal in area to a given parallelo- 
gram 49 

To construct a square equal to a given circle.. 49 

To inscribe a square within a given circle 50 

To describe a square without a given circle 50 

To construct an octagon in a given square 50 

To describe an octagon about a given circle 51 

To construct a circle equal in area to two given circles... 51 
To construct a square equal in area to two given squares . . 52 
To draw a straight line equal in length to a given portion 

of the circumference of a circle 52 

To inscribe a hexagon in a given circle 53 

To find the correct position of an eccentric in relation to 

the crank, the travel of the slide valve being given.. 53 
To lay out the throw of an eccentric for operating a slide 

valve 53 

To describe a cycloid, the diameter of the generating circle 

being given 54 

To develop a spiral with uniform spacing 54 

To construct a 90° angle or a right angle 55 

To construct a 60° angle 55 

To construct a 45° angle 56 

To construct a 30° angle 56 



INDEX 619 

Page 
MENSURATION OF PLANE SURFACES: 

Area of a circle ....... 59 

Circumference of a circle 59 

Area of a semi-circle 59 

Circumference of a semi-circle 59 

Area of an annular ring 59 

Outer circumference of an annular ring 59 

Inner circumference of an annular ring 60 

Area of an ellipse 60 

Area of a flat oval 60 

Area of a parabole 61 

Area of a square 61 

Circumference of a square , 61 

Area of a rectangle . . ... 61 

Circumference of a rectangle. 61 

Area of a parallelogram 61 

Area of a trapezoid 62 

Area of an equilateral triangle 62 

Circumference of an equilateral triangle ...„ 62 

Area of a right angle or an isosceles triangle 62 

Circumference of a right angle or an isosceles triangle 63 

Area of an hexagon 63 

Circumference of a hexagon 63 

Area of an octagon 63 

Circumference of an octagon 63 

Area of any regular polygon 63 

Circumference of any regular polygon 61 

MENSURATION OF VOLUME AND SURFACE: 

Cubic contents of a sphere ...64 

Superficial area of a sphere 64 

Cubic contents of a hemisphere 64 

Superficial area of a hemisphere 65 

Cubic contents of a cylindrical ring 65 

Superficial area of a cylindrical ring 65 

Cubic contents of a cylinder * 65 

Superficial area of a cylinder 65 

Cubic contents of a cone 66 

Superficial area of a cone _.. 66 



620 INDEX 

Page 

Cubic contents of the frustum of a cone 66 

Superficial area of the surface of a frustum of a cone 66 

Contents of a cube 67 

Superficial area of a cube 67 

Cubic contents of a rectangular solid 67 

Superficial area of a rectangular solid 67 

Cubic contents of a pyramid 68 

Superficial area of a pyramid „ . 68 

MENSURATION OF TRIANGLES: 

Base of a right-angle triangle when the perpendicular and 
hypothenuse are given 68 

Perpendicular of a right-angled triangle when the base and 
hypothenuse are given 68 

Hypothenuse of a right angle triangle when the base and 
perpendicular are given 69 

Perpendicular height of any oblique angled triangle 69 

Area of any oblique angled triangle when only three sides 
are given 69 

Height of the perpendicular and the two sides of any tri- 
angle inscribed in a semi-circle, when the base of the 
triangle and the location of the perpendicular are given 70 

PROPERTIES OP THE CIRCLE: 

Circumference 71 

Diameter 71 

Area 71 

Side of square of equal area. 71 

Diameter of circle equal in area to square 71 

Versed sine 71 

Chord of an arc 71 

Radius 71 

Length of any line perpendicular to the chord of an arc 72 

Length of any arc of a circle when the chord of the arc and 
the chord of half the arc are given 72 

APPLIED MECHANICS: 

The lever 85 

The wheel and pinion 87 

The pulley or sheave 89 



INDEX 621 

Page 

The inclined plane 92 

The wedge 93 

The screw 94 

The safety valve 96 

Gravity and the velocity of falling bodies 98 

Specific gravity, center of oscillation and centrifugal force. 102 

Percussion 108 

Capillary attraction 108 

Friction 109 

Belt pulleys 110 

Gear wheels Ill 

Diametrical pitch system of gears 113 

PROPERTIES OF STEAM: 

To calculate the advantage of using steam expansively 120 

Condensation of steam 121 

Pressure and expansion of steam 122 

Volume and pressure of steam 122 

Point of saturation of steam 122 

Expansion of steam 123 

Superheated steam 123 

Density, pressure and temperature of steam 123 

Flow of steam 124 

Pressure of gas or vapor 124 

Velocity of efflux of steam 125 

Lead of the valve 126 

Absolute temperature 126 

Specific heat 127 

Heat .127 

THE INDICATOR: 

Indicated horsepower of an engine 133 

Indicator diagram 137 

Average pressure „ . . 137 

HORSEPOWER: 

Horsepower of steam engines 143 

Horsepower of gas and gasoline engines 150 

Electrical horsepower ... 152 

Horsepower of gear wheeiS .153 



622 INDEX 

Page 
ELECTRICITY: 

Electrical rules and formulas 159 

The volt 159 

The ampere 159 

The ohm . . . . 160 

Ampere-hour 161 

Watt-hour 161 

MEASURING DEVICES: 

Micrometers 165 

How to read a micrometer 168 

To read a micrometer to ten-thousandths 169 

Screw thread micrometer 171 

Ratchet stop for micrometers 172 

Sheet metal micrometer 172 

Inside micrometer gauge 174 

Caliper gauges 175 

Limit gauges J 75 

Depth gauges 177 

Surface gauges 179 

The vernier caliper ana its use 182 

The combination bevel. 184 

The protractor 186 

Gauges 1*90 

Test indicator 191 

Speed indicators 195 

MACHINISTS' TOOLS: 

Bevel protractor 201 

Combination bevel protractor 202 

Bevel 203 

Spring calipers 203 

Screw thread calipers 204 

Keyhole caliper 204 

Firm joint caliper 204 

Adjustable firm joint caliper 205 

Caliper rule — 206 

Caliper square 206 

Center punch 208 

Combination square „ . . 209 



INDEX 623 

Page 

Depth gauge 210 

Drill and wire gauges 210 

Dividers 212 

Hammers 212 

Key seat rule 212 

Hand vises 212 

Levels 212 

Micrometers 213 

Pliers 213 

Plumb-bob 214 

Surface gauge 215 

Screw drivers 216 

Screw-pitch gauges 217 

Steel scales or rules 217 

Standard square 218 

Thread-gauge 218 

Tram-points 218 

Try square 218 

Wrenches 219 

SHOP TOOLS: 

Angular bit-stock 223 

Arbors 223 

Belt clamp 224 

Belt and lace cutters 224 

Bench shears 224 

Blacksmith's drill 226 

Blacksmith's forge ' 226 

Blacksmith's tools 228 

Breast drills 228 

Breast drill attachment 230 

Center drin and countersink 231 

Chucks 231 

Clamps 234 

Cold chisels 234 

Counterbores 235 

Depth gauge 236 

Dies 236 

Drills and drill-holders , . .237 



624 INDEX 

Page 

Drill grinders 238 

Emery-wheel dressing tools 238 

Gauges , 238 

Hack saws 241 

Lathe dogs 242 

Lathe threading tool 242 

Levels 242 

Micrometer 244 

Planer jacks . 245 

Power hack saw 246 

Taps 247 

Vises 247 

Wrenches - 251 

MACHINE TOOLS: 

Erecting machine tools 255 

BOLT-CUTTERS: 

Bolt-cutter head 256 

Bolt-cutter - 257 

One and one-half inch motor driven bolt-cutter 259 

Three-inch motor driven bolt-cutter 260 

BORING MACHINES: 

Cylinder boring machine 263 

Horizontal boring machine 263 

Horizontal drilling machine 266 

Vertical boring machine 268 

DRILL-PRESSES: 

Friction-driven drill-press .272 

Gang drill-press 273 

Motor-driven drill-presses 274 

Upright drill 277 

Radial drill 277 

Radial drill 282 

Compound drill-press table 284 

Gear change box 284 

Tapping attachment for drill-presses 285 

Tire drill 286 

Almond drill chuck 288 



INDEX 625 

Page 

Skinner drill chuck 288 

Cushman drill chuck 283 

Twist drills 288 

Horizontal drill press 289 

GEAR CUTTING MACHINES: 

Fellow's gear shaper 290 

Whiton gear cutter 292 

Automatic gear cutter 293 

The sizing and cutting of gears 294 

Cutting gears 299 

Tooth flanks undercut 303 

Bevel gears 301 

Comparative sizes of gear teeth 304 

Gear tooth caliper 304 

GRINDING MACHINES: 

Automatic saw grinder 308 

Bench grinder 308 

Grinding attachment 309 

Knife grinding machine 309 

Motor driven drill grinder 311 

Motor driven water grinder 311 

Plain grinding machines 311 

Polishing or grinding machine 313 

Saw grinder . . .- 314 

Surface grinder 314 

Water grinding attachment 316 

Water grinding machine 317 

Water tool grinder 318 

Care and use of grinding machines 318 

Emery wheels 322 

Internal grinding 322 

Speed of work and cut of wheel 324 

Method of driving universal grinder 324 

Accuracy of the work 324 

Back rest 327 

Head stock 328 

Vibration of the work 328 



626 INDEX 

Page 

Grinding work of the headstock 33(1 

Wheel spindles and boxes 33C 

THE LATHE: 

Erecting lathes 332 

Automatic feed turret lathe 333 

Back-geared lathe 335 

Combination turret lathe 337 

Bench lathe 339 

Double-head manufacturer's lathe 339 

Fourteen-inch lathe .. . 341 

Motor-driven lathe 342 

Motor-driven turret lathe 344 

Pattern maker's lathe 346 

Plain turret lathe 346 

Quick change-gear lathe 348 

Quick change-gear engine lathe 353 

Quick change-gear 18-inch lathe 353 

Speed lathe 353 

Tool maker's lathe 357 

Universal turret lathe 355 

The automatic turret 360 

Block rest with chasing stop 361 

Full swing rest 361 

Lathe apron 363 

Reverse plate 364 

Taper attachment 364 

Thread chasing dial 365 

Three tool shafting rest 36f 

Tool posts . 367 

Cutting speed and feed of lathe tools 368 

Cutting tools for the lathe 37G 

Screw-cutting 376 

Using the center gauge 373 

Work done on the turret lathe 381 

MILLING MACHINES: 

Erecting milling machines ... 383 

Adjusting milling machines '. 381 

Use of milling machines , 38i 



INDEX 627 

Page 

Milling machine — 387 

Automatic-feed milling machines 389 

Dividing head and center 391 

Motor-driven milling machines 392 

Motor-driven universal millers 395 

Simple indexing 397 

Compound indexing 402 

Cam cutting attachment 404 

Circular milling attachment 405 

Cutter grinding attachment 406 

High speed milling attachment 407 

Lincoln milling machine 408 

Geared pump 4?8 

Gear cutting attachment 408 

Hand milling attachment 410 

Plain vise 411 

Quill gear cutting attachment 411 

Rack cutting attachment 412 

Universal versus plain millers 413 

Plain milling machine 415 

Bench milling machine 417 

Vertical spindle milling machine 418 

Slotting attachment 418 

Swivel vise 421 

Tool maker's universal vise 421 

Universal index centers 422 

Vertical spindle milling attachments 425 

Differential dividing head 427 

Speed for milling cutters 427 

Milling cutters 433 

Milling operations ^ 433 

PLANERS: 

Planing operations 437 

43x43-inch planer 437 

32-inch planer 438 

24-inch planer 441 

Cutting speed and feed of planer tools 442 

Planer jacks 445 



628 INDEX 

Page 
SHAPERS: 

Crank shaper 447 

High duty crank shaper 448 

Motor-driven crank shaper 451 

Pull-cut Traverse head shaper 452 

Rack shaper 455 

Speed change gear box 457 

16-inch back-geared shaper ......^ 458 

Shaper centers 460 

SLOTTING MACHINES: 

10-inch slotter 461 

18-inch slotter 462 

Cutting key-ways in a slotter ^464 

AUXILIARY MACHINE TOOLS: 

Arbor press 467 

Bolt-cutting and threading machines 470 

Brass finisher's lathe , 474 

Centering machine 476 

Cold saw cutting-off machine 478 

Cutting-off machine 478 

Grinder attachment 481 

Hub-forming machine 481 

Key-seating machine 483 

Pipe-threading and cutting machine 484 

Power presses 487 

Drop press 488 

Power press 489 

Pulley turning lathe 493 

Punch and shear 493 

Screw shaving machine 496 

Screw threading die holder 496 

Valve milling machine 498 

PORTABLE TOOLS: 

Boring bar 503 

Chain hoists ... 503 

Electric motor 504 

Hand drill-press „ 50? 



INDEX 629 

Page 

Forge 1... o 505 

Key-seating machine . . . - .. . .507 

MISCELLANEOUS TOOLS: 

Slide rests 511 

Tool holders 512 

Tapping attachments 513 

Hand and follower rests , . . 517 

Wet tool grinder 517 

Countershafts 517 

Magnetic chuck 520 

Demagnetizer 521 

PLAIN AND SPIRAL INDEXING DEVICES: 

Plain index center 525 

Universal head 526 

Universal spiral cutting head 527 

NOTES ON THE WORKING OF STEEL: 

Steel 531 

Case-hardening 531 

Case-hardening with prussiate of potash 531 

Case-hardening mixtures 531 

Hardening and tempering steel 533 

To prevent blow-holes in steel 534 

Notes on steel 534 

Case-hardening wrought iron 535 

Tempering tool steel 535 

GAS FURNACES: 

Oil tempering furnace 540 

Bench forge - 540 

Twist drill hardening furnace 542 

Tool room forge 542 

Positive pressure blower ....542 

SHOP TALKS .549 

SHOP KINKS 555 

MEDICAL AID 579 

TABLES 585 



630 INDEX 

TABLES. 

Page 
1 — Squares, cubes, square and cube roots and reciprocals of 

numbers from 1 to 500 22 

2— Logarithms of numbers from 100 to 999 3? 

3— Areas of circles from 0.1 to 99.9 73 

4 — Circumferences of circles from 0.1 to 99.9 78 

5— Velocity of falling bodies 101 

6 — Specific gra\ ity and weight per cubic foot of metals . . . 103 
7 — Specific gravity and weight per cubic foot of substances. 104 
8 — Specific gravity and weight per cubic foot of liquids. . .105 

9 — Comparative weights of different metals, etc 106 

10 — Dimensions of involute tooth spur gears 116 

11 — Work done by steam during admission and expansion. 121 
12 — Average steam pressure on piston in pounds per square 

inch 148 

13 — Diametral pitch in inches .297 

14 — Circular pitch in terms of diametral pitch 297 

15 — Depth of space and thickness of tooth in spur wheels, 

when cut with involute cutters 299 

16 — Emery wheel speeds 331 

17 — Cutting speeds and feeds for lathe tools 369 

18 — Change gears for screw-cutting 378 

19 — Milling machine index tables 400 

20 — Milling machine cutting speeds 430 

21— Speeds for milling-cutters 432 

22— Speed of bolt-cutter dies - 473 

23— Metric system — Measures of length 586 

24 — Measures of weight 586 

25 — Measures of capacity 586 

26 — Decimal equivalents of millimeters. 587 

27 — Taper per foot in degrees 588 

28 — Machine or nut taps 589 

29 — Hob or master taps 590 

30 — Decimal parts of an inch 591 

31 — Melting points of alloys of tin, lead and bismuth .591 

32— Speed of twist drills 532 

33— Thread parts of acme thread ......... o 593 



INDEX 631 

Page 

34— Double depth of V and U. S. threads 594 

35 — Diameter of number twist drills and steel wire gauge. =595 

36 — Dimensions of wrought-iron pipe 596 

37 — Length of threads cut on bolts 597 

38— English or Whitworth pipe threads 597 

39 — Weight per foot of square and round iron ba.s 598 

40 — Properties of metals 599 

41— U. S. or Franklin Institute threads 600 

42— V standard thread 600 

43— Whitworth or English standard. 600 

44 — Melting, boiling and freezing point of various sub- 
stances 601 

45— Drill list for U. S. standard thread 602 

46 — Machine screw top drills 602 

47— Drill list for V-thread taps 603 

48 — Proportionate weight of castings to weght of wood 

patterns 604 

49 — Letter sizes of twist drills 605 

50— Sizes of tap drills 605 

51 — Weight and arc of square and round steel and the cir- 
cumference of round bars 606 

52 — Size and weight of hot pressed hexagon nuts, United 

States standard 608 

53— Size and weight of hot pressed square nuts, United 

States standard 609 

54— Weight per foot of flat bar steel 610 

55 — Weight per foot of flat bar iron .611 

56 — Wire gauges in use in the United States 612 

57 — Weight of sheet iron and steel. ..,.., 614 

58 — Allowances for running and force fits 616 



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ful formulas, by James H. 
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L. Elliott Brookes* 
16mo. Popular Edition. 
Full cloth. 

Price net, SI. 00 

Edition de Luxe. FulJ 

leather limp. 

Price net, $i.SO 



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THE AUTOMOBILE HAND-BOOK 

OVER 200,000 SOLD 

By ELLIOTT BROOKES, Assissted by Other Weil-Known Experts 

Revised and Enlarged New Edition— The largest and most practical 

work published. Used by all up-to-date automobile schools as 

their everyday text-book. over 720 pages and 

over 329 illustrations. Full Leather Limp, Round 

Corners, Red Edges. Price, $2.00. 

At the present time nearly all automobile 
troubles or breakdowns may, in almost 
every case, be traced to the lack of knowl- 
edge or carelessness of the owner or opera- 
tor of the car, rather than to the car itself. 
The automobile hand book is a work of 
p actical information for the use of owners, 
operators and automobile mechanics, giv- 
ing full and ccncise information on all 
qm otions relating to the construction, care 
and opera on of gasoline and electric auto- 
mobiles, including road troubles, motor 
troubles, -rbureter troubles, ignition 
troubles, battery troubles, clutch troubles, 
starting troubles. With numerous tables, 
useful rules and formula?, wiring diagrams 
and over329illustrations. 

Special efforts have been put forth to 
treat the subjects of ignition, and igni- 
tion devices, in a manner befitting their 
importance. A large section has been 
devotf d to t ese subjects, including bat- 
teries, primary and secondary, magnetos, 
carburators, spark plugs, and in fact all devices used in connection with 
the production of the spark. Power transmissio is thoroughly discussed, 
and the various systems of transmitting the power from the motor to the 
driving axle are analyzed and compared. 

The perusal of this work for a few minutes when troubles occur, will 
often not only save time, money, and worry, but give greater confidence 
in the car, with regard to its going qualities on the road, when properly 
and intelligently cared for. 

A WORD TO THE WISE 

The time is at hand when any person caring for and operating any 
kind of self-propelling vehicle in a public or private capacity, will haVe to 
undergo a rigid examination before a state board of examiners and secure 
a license before they can collect their salary or get employment. 

Already New York State has enacted such z. law and before long, with 
a positive certainty every state in the Union will pa»s such an ordinance 
for the protection of life and property. 

Remember this is a brand new book from cover to cover, just from 
the press — New Edition — and must not be confounded with any former 
editions of this popular work. 

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The Practical Gas £? 
Oil Engine hand .boo k 



A MANUAL of useful in- 
•**■ formation o n the care, 
maintenance and repair of Gas 
and Oil Engines. 

This work gives full and 
clear instructions on all points 
relating to the care, mainte- 
nance and repair of Stationary, 
Portable and Marine, Gas and 
Oil Engines, including How to 
Start, How to Stop, How to Ad- 
just, How to Repair, How to 
Test. 

Pocket size, 4x6H 
232 pages. With numerous 
rules and formulas and dia- 
grams, and over 70 illustrations 
by L. Elliott Brookes, au- 
thor of the "Construction of a 
Gasoline Motor," and the "Au- 
tomobile Hand-Book." 

This book has been written 
with the intention of furnishing 
practical information regarding 
gas, gasoline and kerosene engines, for the use of owners, operators and 
others who may be interested in their construction, operation and man- 
agement. 

In treating the various subjects it has been the endeavor to avoid all 
technical matter as far as possible, and to present the information given 
in a clear and practical manner. 

f 6mo. Popular Edition— Cloth. Prico $1.00 

Edition de Luxe— Full LeeUher Limp. Price ... 1.56 

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The Calculation of Horse 
Power Made Easy : : ; 

By L. ELLIOTT BROOKES 

Author of "Gas and Oil Engine Hand-Book," 

"The Automobile Hand-Book," Etc. 

Size, 5x7%. 80 Pages, Illustrated. Cloth, 75 Cents 




«» 



THIS work deals in a practical and non- 
technical manner with the calculation 
of the power of Steam Engines, *Explo- 
sive and Electric Motors. 

Particular attention has been given to the 
full explanation of the elementary principles 
upon which the calculations are based. 

It has been the endeavor to present in as 
simple a manner as is possible, a number of 
useful rules and formulas that may be of 
great value to Engineers, Machinists and 
Designers in calculating horse power. 

Rules for plotting steam engine diagrams 
by arithmetical, geometrical and graphical 
methods are given and fully explained, also 
the method used in plotting the diagram oi 
an explosive motor. 

This work covers many points regarding 
the calculation of horse power and useful 
information not hitherto published in a single 
wlurne, and includes Calculated, Brake and Indicated horse power, Point of 
cut-off and average steam pressure, Horse Power of Explosive Motors, Degree 
of Compression and Combustion Chamber Dimensions, Indicator Diagrams of 
Steam Engines and Explosive Motors, also tables of Average Steam Pressure, 
Areas of Circles, Squares of Diameters of Circles, Natural Logarithms of Num- 
bers, Thermo-dynamic Properties of Gasoline and Air, Common Logarithms 
of Numbers, and Mensuration of Surface and Volume. 

Tne term " Explosive Motor" includes Gas, Gasoline and Oil Engines. 




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STANDARD BOOKS for 

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MODERN WIRING DIAGRAMS 
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300 pages, 225 illustrations, 
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PRACTICAL ARMATURE AND MAGNET WINDING 
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Electrician's Operating and Testing 
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Farm Engines and How to Run Them — 

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Gas arid Oil Engine Hand Book — 

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Heating and Lighting Railway Passen- 
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Locomotive Breakdowns, with Questions 

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Mechanical Drawing and Machine Design 

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Motorman, How to Become a Successful. 

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Millwright's Practical Hand Book — Swin- 
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Modern American Telephony In All Its 
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Picture Making for Pleasure and Profit — 

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Railway Roadbed and Track, Construc- 
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Railway Shop Up7to-Date — Haig. Illus- 
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Sheet Metal Workers' Instructor — Rose. 

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Sign Painting, The Art of — Atkinson... 3.00 

Stair Building and Hand Railing — Hodg- 
son. Illustrated 1.00 

Steam Boilers — Swingle. Illustrated 1.50 

Steel Square, A Key to — Woods. , 1.50 . . 

Steel Square, Vol. I — Hodgson. Illus- 
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Steel Square, A B C — Hodgson 50 .. 

Steel Construction, Practical — Hodgson. 

Illustrated 50 .. 

Storage Batteries — Niblett 50 . . 

Sho* Cards, A Show At — Atkinson and 

Atkinson 3.00 .. 

Stonemasonry, Practical, Self-Taught — 

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Telephone Hand-Book— Illus- 
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Timber Framing, Light and Heavy — 

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Toolsmith and Steel Worker — Holford. 

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16 mo., Cloth, Illustrated. Price, each, $0.60 

Exterior Painting, Wood, Iron and Brick. 
Interior Painting, Water and Oil Colors. 
Colors, What They Are and What to Expect 

from Them. 

Graining and Marbling. 
Carriage Painting. 
The Wood Finisher. 






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